This article reflects Montana law and enforcement conditions as of June 2026. Montana has a statewide ban on sanctuary policies under House Bill 200 (signed March 31, 2021, codified at Montana Code Annotated 2-1-601 through 2-1-605), which prohibits state agencies and local governments from restricting employees from sharing immigration status information with federal authorities and requires compliance with lawful ICE detainer requests for individuals already in custody. Attorney General Austin Knudsen and Governor Greg Gianforte actively enforce HB 200: in February-March 2026, Helena's City Commission voted a non-cooperation resolution, was investigated under HB 200, faced potential loss of state grants and $10,000-per-five-day fines, and voted to rescind the resolution in March 2026. Montana Highway Patrol (MHP) signed a 287(g) Task Force Model agreement with ICE on February 20, 2025. Camp East Montana, ICE's largest immigration detention facility, opened on U.S. Army property in eastern Montana in August 2025 and held approximately 1,600 detainees as of late February 2026 in a facility contracted for 5,000. The Migration Policy Institute estimated Montana had approximately 6,000 unauthorized residents in 2023, the lowest per-capita undocumented population of any U.S. state. Verify current enforcement conditions and detainer policies with the ACLU of Montana at aclumontana.org.
Where Montana Stands
Montana is one of the most distinctive stories in this 50-state series for reasons that have little to do with the size of its immigrant population. By the most recent estimates available, Montana has approximately 6,000 unauthorized residents, the lowest per-capita undocumented population of any state in the country. Yet Montana is also home to Camp East Montana, ICE's largest immigration detention facility, which opened on a U.S. Army base in eastern Montana in August 2025 and was contracted to hold up to 5,000 detainees. The gap between who lives in Montana and what Montana hosts for the federal detention infrastructure is the editorial heart of this article.
Montana's enforcement framework is enforcement-aligned at the state level: a 2021 sanctuary ban with real financial penalties, an AG and governor who have publicly and aggressively enforced it against Helena, a statewide Montana Highway Patrol 287(g) agreement, and tribal 287(g) agreements. But local law enforcement across Montana's vast rural counties has described its role as limited, focused on criminal matters rather than civil immigration enforcement, and several major cities including Bozeman and Missoula have stated their police do not conduct immigration enforcement as a matter of practice.
The Helena saga is the most vivid illustration of the tension between state law and local governance in Montana's immigration story. Helena's City Commission voted in January 2026 to adopt a resolution directing local police not to assist federal immigration enforcement. The governor and AG launched an investigation, threatened fines and grant loss, and issued a cease-and-desist letter. By March 2026, facing potential loss of millions in state grants, the commission voted to rescind the resolution. The commission then attempted to draft a revised resolution, but the AG warned he would challenge any new ordinance. As of spring 2026, Helena remained without a formal local immigration policy and its commission was unable to reach consensus on next steps.
Part 1: What Federal Immigration Law Actually Says
Immigration enforcement is exclusively a federal function under the Immigration and Nationality Act (INA). The federal government controls who may enter, remain in, and be removed from the United States. State and local governments cannot create their own immigration enforcement systems that conflict with the INA.
The Tenth Amendment anti-commandeering doctrine, established in Printz v. United States (1997), means the federal government cannot compel state and local agencies to enforce federal immigration law. Montana agencies that cooperate with ICE do so voluntarily. However, HB 200 limits the range of choices available to Montana's local governments: they cannot formally adopt policies restricting the information-sharing floor that HB 200 requires.
Section 287(g) of the INA is the voluntary delegation mechanism through which ICE trains and authorizes local agencies to perform certain immigration enforcement functions. Montana Highway Patrol signed a Task Force Model agreement authorizing trained MHP troopers to make immigration arrests during routine enforcement duties. Several tribal law enforcement agencies have Tribal Task Force Model agreements. The Gallatin County Sheriff's Office has a Warrant Service Officer agreement, authorizing deputies to execute ICE administrative warrants at the county jail. Garfield County signed a Task Force agreement in August 2025.
ICE detainers, Form I-247, are administrative requests, not court orders. HB 200 requires law enforcement officers in Montana to comply with lawful immigration detainer requests for individuals already in their custody. This is an important distinction from the broader custody question: HB 200 does not authorize holding someone solely because ICE wants to question them; it requires compliance with detainer requests for individuals who are already lawfully in custody on other charges. Whether this extends to holding someone beyond their scheduled release date solely on a civil detainer has not been definitively litigated in Montana.
Arizona v. United States (2012) is the controlling preemption precedent. Montana's enforcement framework, structured as facilitation of voluntary federal enforcement and mandatory information sharing, is designed within the constitutional boundaries the Court established in Arizona. HB 200's information-sharing mandate raises the question of whether states can compel local agencies to provide information to federal authorities in ways that go beyond what federal law requires - that question has not been definitively resolved.
Part 2: Montana State Law and Enforcement Infrastructure
House Bill 200 - The Montana Sanctuary Policy Ban (Signed March 31, 2021)
Montana House Bill 200, signed by Gov. Gianforte on March 31, 2021, and codified at Montana Code Annotated 2-1-601 through 2-1-605, is the foundation of Montana's immigration enforcement framework. It passed the legislature with only Republican votes and was opposed by the Montana League of Cities and Towns.
HB 200 prohibits state agencies and local governments from enacting or enforcing any policy that restricts government employees from sending to, receiving from, exchanging with, or maintaining for a federal, state, or local government entity information regarding a person's citizenship or immigration status for a lawful purpose. It also requires that law enforcement officers comply with lawful ICE immigration detainer requests for individuals already in their custody.
Enforcement mechanisms under HB 200 are meaningful. The Montana Attorney General has authority to investigate local governments and state agencies for potential violations, to file civil actions in Lewis and Clark County District Court, and to seek fines of up to $10,000 for every five days of noncompliance with state law following notification. The Montana Department of Commerce may withhold grant funding from noncompliant jurisdictions, including Coal Endowment Program and Montana Coal Board funds. A jurisdiction has 14 days from notification of a violation to come into compliance before fines begin.
The Helena investigation in 2026 was the first time the AG's office formally applied HB 200 to a local government. Helena's resolution, passed 4-1 on January 26, 2026, directed local police not to assist federal immigration enforcement, not to share sensitive information outside city government except under a court order, and to request that federal immigration officers identify themselves and remove masks. Gov. Gianforte and AG Knudsen launched a formal investigation on February 11, 2026, and the AG issued a cease-and-desist letter in March 2026. Helena's city officials argued the resolution complied with HB 200 because it only addressed civil immigration enforcement and did not restrict detainer compliance for individuals already in custody on other charges. The AG rejected that interpretation. Helena voted to rescind the resolution on March 26, 2026, facing potential loss of millions in grant funding.
Following the rescission, the AG warned Helena directly in writing that he would investigate any revised ordinance the city might adopt and that compliance with HB 200 was not a collaborative enterprise. As of spring 2026, Helena's commission was unable to reach consensus on next steps, some commissioners wanting to try again with a modified policy, others concerned about continued legal exposure.
Montana Highway Patrol - 287(g) Task Force Model, February 20, 2025
Attorney General Knudsen announced on February 20, 2025, that Montana Highway Patrol (MHP) troopers and Division of Criminal Investigation (DCI) agents had signed a 287(g) Task Force Model agreement with ICE. The agreement authorizes trained MHP troopers to arrest undocumented individuals encountered during the course of their normal duties and work with ICE on deportation. Montana was among the first states to sign a statewide Task Force agreement under the Trump administration's expanded 287(g) program.
The practical effect is that any traffic stop or law enforcement encounter with an MHP trooper in Montana carries potential immigration enforcement authority. Montana's highway system, with major interstate corridors including I-90, I-15, and I-94 traversing vast distances between cities, means that routine traffic enforcement can occur far from any significant immigrant community with no other law enforcement presence for miles.
Tribal 287(g) Agreements
Several tribal law enforcement agencies in Montana have Tribal Task Force Model 287(g) agreements with ICE. This is a model specifically designed for tribal nations, allowing tribal law enforcement officers to perform certain immigration enforcement functions on tribal lands. Montana's significant tribal land base, spanning the Blackfeet, Crow, Flathead, Fort Belknap, Fort Peck, and Northern Cheyenne reservations, means tribal 287(g) agreements extend the enforcement infrastructure into a significant portion of the state's geography. Families living on or near Montana's reservations should be aware of the tribal law enforcement posture in their specific area.
Gallatin County and Other Local Agreements
Gallatin County Sheriff's Office holds a Warrant Service Officer (WSO) 287(g) agreement and has had it for approximately five years as of early 2026. Under the WSO model, ICE reviews individuals booked into the Gallatin County Detention Center, identifies people for detainer warrants, and a trained GCSO deputy serves those warrants. Sheriff Dan Springer described the role as limited and focused on criminal matters.
Garfield County Sheriff's Office signed a Task Force Model agreement in August 2025, covering the 4,800-square-mile eastern Montana county. Undersheriff Aaron Conner said the agreement is a tool for enforcement in an area where it takes 45 minutes to reach calls on some parts of the county and where hunting and recreation traffic adds to highway volume. As of early 2026, he noted the department remained unsure about federal reimbursement timing.
Bozeman's police chief stated in February 2026 that his department's focus is public safety and that immigration enforcement is not within its duties. Bozeman does not have a 287(g) agreement. Missoula's mayor and police chief posted a public explanation that local officers do not ask about immigration status during routine public interactions and do not enforce federal immigration law. Missoula does not have a 287(g) agreement and was reviewed but not formally investigated by the AG, who found no formal written policy comparable to Helena's.
Camp East Montana - ICE's Largest Detention Facility
In August 2025, U.S. Immigration and Customs Enforcement opened Camp East Montana on a U.S. Army base in eastern Montana. The facility was contracted to hold up to 5,000 detainees, making it the largest immigration detention facility in the United States. A $1.3 billion contract was awarded to operate the facility. The Army awarded and administered the contract initially, transferring administration to ICE in October 2025.
A June 2026 Government Accountability Office (GAO) report on Camp East Montana documented serious problems. The facility held approximately 1,600 detainees as of late February 2026, far below its contracted capacity of 5,000. Because the contract required the Army and ICE to pay the full cost of meals and operational services regardless of occupancy, the government paid for services for a facility that was less than a third full. The GAO estimated tens of millions of dollars in waste. In April 2026, ICE terminated the original contract for convenience and selected a new contractor, but had not yet incorporated cost-saving measures into the new contract.
The GAO also found that Camp East Montana opened without meeting key detention standards. At opening, the facility lacked perimeter security cameras, outdoor recreation space, and adequate space for attorney and family visitation. The GAO's June 2026 report called for immediate corrective action.
Camp East Montana is the most consequential piece of immigration infrastructure in Montana for families across the country: it is not primarily a facility holding Montana residents. It is a national detention hub located in Montana. Individuals detained in other states and transported to Camp East Montana may have family members far from Montana who need to use the ICE Detainee Locator to find them. If a family member is detained and you cannot locate them through local contacts, locator.ice.gov is essential.
Part 3: How State and Federal Law Interact in Montana
Montana's enforcement framework is enforcement-aligned but internally varied. HB 200 sets a floor: local governments cannot formally restrict information sharing with federal immigration authorities. MHP's statewide Task Force agreement and the tribal 287(g) agreements provide state-level and tribal enforcement authority. But local law enforcement agencies across most of Montana's vast rural counties have described their immigration enforcement role as limited, focused on criminal matters, and not involving proactive immigration enforcement absent a criminal nexus.
The tension between HB 200 and local control is the most legally active question in Montana's immigration picture. Helena's experience showed that HB 200 has real teeth: the AG is willing to investigate, issue cease-and-desist letters, and threaten substantial financial penalties. Other Montana cities, including Bozeman and Missoula, have maintained informal non-enforcement practices without formal written policies, appearing to stay below the threshold that triggered the Helena investigation.
HB 200's detainer compliance requirement is significant but bounded. The law requires compliance with lawful detainer requests for individuals already in custody on other grounds. It does not, by its terms, authorize holding individuals solely because ICE wants to question them if they are not otherwise in lawful custody. The boundary between these two situations, and the extent to which HB 200 requires active detainer holds versus merely prohibits formal anti-detainer policies, has not been judicially resolved in Montana.
Camp East Montana introduces a dimension of Montana's immigration story that is almost entirely about federal authority: the federal government has the authority to establish detention facilities on federal land (U.S. Army bases) anywhere in the country. Montana's state law has no role in Camp East Montana's operations. It is a federal facility, on federal land, operating under federal contracts.
Arizona v. United States (2012) remains the outer framework. Montana's approach, structured around information sharing mandates and voluntary 287(g) cooperation, is designed within constitutional limits. Whether HB 200's compelled information-sharing requirement raises Tenth Amendment concerns has not been definitively litigated.
Part 4: What This Means for Families on the Ground
For immigrant families in Montana, the practical enforcement picture is shaped by three realities: the state law floor that prohibits local non-cooperation policies, the MHP statewide Task Force authority that extends to any highway encounter, and the Camp East Montana facility that can receive detainees from anywhere in the country.
Any MHP traffic stop carries potential immigration enforcement authority. Montana's highways are long and remote, and state troopers are often the only law enforcement present over vast distances. A traffic stop on I-90 crossing the mountains or on I-94 through the eastern plains is a potential immigration encounter.
In cities like Bozeman and Missoula, local police have stated they do not conduct immigration enforcement as a matter of practice. Those statements are meaningful but are not formally protected by written policy - the Helena saga demonstrated that formal written non-cooperation policies are vulnerable to HB 200 enforcement. The informal practice can continue, but it cannot be codified in a way the AG would challenge.
Gallatin County (Bozeman) has a WSO agreement: ICE can place detainers on individuals in the county jail, which are then served by trained deputies. Garfield County in eastern Montana has a Task Force agreement.
Camp East Montana, while primarily a national facility rather than a local one, matters for Montana families in two ways. First, if a family member is detained anywhere in Montana, they may be transferred to Camp East Montana. Second, the facility's documented early deficiencies, including lack of attorney and family visitation space, make it important for families of people held there to contact legal services immediately and use the ICE Detainee Locator.
Montana's small unauthorized immigrant population of approximately 6,000 people means that enforcement operations are not concentrated in the way they are in states with hundreds of thousands of undocumented residents. ICE enforcement in Montana tends to be incident-driven rather than population-scale. However, a June 2025 arrest of six Venezuelan gang members in Gallatin County was specifically cited by the AG when announcing the MHP 287(g) agreement, and MHP obtained detainers on 36 people from September 2025 through January 2026. The numbers are small, but the statewide infrastructure is in place.
Part 5: What You Can Actually Do
If ICE or MHP Comes to Your Home
Do not open the door. Neither ICE nor MHP can legally enter a home without a judicial warrant signed by a judge. An ICE administrative warrant, Form I-200 or I-205, is signed by an immigration officer, not a judge, and does not authorize entry into your home. Ask through the closed door whether the warrant is signed by a judge. If it is not, you may say clearly that you do not consent to entry.
You have the right to remain silent. You are not required to answer questions about your birthplace, how you entered the country, or your immigration status. This right applies regardless of immigration status. Say: 'I am exercising my right to remain silent. I want to speak with a lawyer.'
Do not sign anything without speaking with an immigration attorney. Signing voluntary departure forms or other removal documents can permanently waive important legal rights.
If stopped by MHP on a Montana highway, you have the same right to remain silent about immigration status. MHP troopers with Task Force authority can make immigration arrests during traffic stops. Stay calm, exercise your rights, and do not physically resist.
If a Family Member Is Detained
Use the ICE Online Detainee Locator at locator.ice.gov immediately. If a family member is detained in Montana, they may be held at Camp East Montana, Gallatin County Detention Center, or another facility. Camp East Montana's documented early deficiencies in attorney and family visitation space make early contact with a lawyer critical. You will need the person's country of birth and either their full name and date of birth or their A-Number (Alien Registration Number).
Call the ICE Detention Reporting and Information Line: 1-888-351-4024.
Call the EOIR Immigration Court Information Line: 1-800-898-7180 for hearing dates and case status.
Contact the ACLU of Montana: aclumontana.org. The ACLU of Montana has been the primary civil rights organization monitoring HB 200 enforcement and 287(g) developments.
Contact the Montana Immigrant Justice Alliance (MIJA): montanajustice.org. MIJA provides legal services and advocacy for immigrants in Montana.
Know the Risk Points in Montana
Any MHP traffic stop carries potential immigration enforcement authority statewide. Montana's vast distances mean state troopers are often the only law enforcement present across large stretches of highway.
Gallatin County (Bozeman) has a WSO 287(g) agreement. Any booking into the Gallatin County Detention Center can result in an ICE detainer.
Garfield County in eastern Montana has a Task Force agreement. Tribal law enforcement agencies on several reservations have Tribal Task Force agreements.
Camp East Montana in eastern Montana is ICE's largest detention facility and can receive detainees from anywhere in the country. If a family member is detained and the locator shows an eastern Montana location, contact an attorney immediately regarding visitation and legal access.
Formal non-cooperation policies at the city level are legally vulnerable under HB 200. The Helena saga shows the AG will investigate and threaten financial penalties against any formal written policy limiting immigration cooperation.
Part 6: Legal Resources in Montana
ACLU of Montana: aclumontana.org. The ACLU of Montana's legal director has been publicly critical of the 287(g) expansion and has monitored HB 200 enforcement throughout 2025-2026.
Montana Immigrant Justice Alliance (MIJA): montanajustice.org. MIJA provides direct legal services to immigrants and has been active in advocacy around Camp East Montana conditions.
Immigration Advocates Network: immigrationadvocates.org. The national legal aid finder allows searching for immigration legal aid organizations by state and county.
National Immigrant Justice Center (Chicago): immigrantjustice.org. NIJC has experience with detained individuals at large ICE facilities and habeas corpus litigation.
EOIR Immigration Court Information Line: 1-800-898-7180.
ICE Detainee Locator: locator.ice.gov.
ICE Detention Reporting and Information Line: 1-888-351-4024.
Summary
Montana is an enforcement-aligned state with several distinctive features. House Bill 200 (signed March 31, 2021, codified at MCA 2-1-601 through 2-1-605) prohibits local governments from adopting policies restricting immigration information sharing with federal authorities and requires compliance with lawful ICE detainer requests for individuals in custody. The law is actively enforced: Helena's January 2026 non-cooperation resolution was investigated, faced fines and grant-loss threats, and was rescinded in March 2026. Montana Highway Patrol signed a statewide 287(g) Task Force agreement in February 2025, giving trained troopers immigration arrest authority across all Montana highways. Gallatin County has a WSO agreement; Garfield County and tribal agencies have Task Force agreements. Bozeman and Missoula maintain informal non-enforcement practices without formal written policies.
Camp East Montana, opened on a U.S. Army base in eastern Montana in August 2025, is ICE's largest detention facility, contracted for 5,000 detainees. A June 2026 GAO report documented waste and conditions deficiencies at the facility. Montana's unauthorized immigrant population is estimated at approximately 6,000, the lowest per-capita of any state. For families in Montana, know your rights at the door, exercise the right to remain silent at any law enforcement encounter, use the ICE Detainee Locator immediately if a family member is detained (especially for Camp East Montana transfers), and contact the ACLU of Montana or MIJA for current legal guidance.
Sources and verification: Montana House Bill 200 (signed March 31, 2021, codified at MCA 2-1-601 through 2-1-605); Montana DOJ press release, 'Attorney General Knudsen Signs Agreement with Trump Administration to Aid in Immigration Enforcement,' February 20, 2025 (dojmt.gov); Montana Governor's Office press release, 'Governor Gianforte, Attorney General Knudsen Investigate Potential Violation of Montana's Sanctuary City Ban,' February 11, 2026 (news.mt.gov); Montana Free Press, 'Where Montana Cities Stand on ICE and Immigration Enforcement,' February 18-23, 2026 (montanafreepress.org); Daily Montanan, 'Under Pressure, Helena City Commission Votes to Rescind Immigration Resolution,' March 26, 2026; Daily Montanan, 'Helena Commission Lacks Consensus for Immigration Next Steps,' April 23, 2026; NBC Montana, 'Montana Attorney General Orders Helena to Halt Sanctuary Policy, Threatens Lawsuit,' March 11-12, 2026; KTVH, 'Montana AG Letter Alleges Helena Violates Law Banning Sanctuary Cities'; Explore Big Sky, 'Breaking Down Montana's Immigration Enforcement Partnerships,' February 18, 2026; GAO Report GAO-26-108886, 'Immigration Detention: Waste and Performance Issues at Camp East Montana,' June 9, 2026; Migration Policy Institute estimate (approximately 6,000 unauthorized residents in Montana, 2023); Arizona v. United States, 567 U.S. 387 (2012); Printz v. United States, 521 U.S. 898 (1997). Volatile items requiring verification: Helena's current local immigration policy status (rescinded March 2026, revised ordinance uncertain; verify with ACLU of Montana); Camp East Montana current operator and detainee population (new contractor as of April 2026); current count of Montana 287(g) agencies. Last verified: June 2026.