Contra Costa MDF in Martinez, CA is a county detention facility operated by the Contra Costa County Sheriff's Office. Most people here are awaiting trial or sentencing - this is not a prison, and most stays are measured in days or months, not years. If someone you care about was just booked here, you have questions. Start with the one that matters most right now.
If you are not certain they are there, the fastest way to confirm is the Contra Costa County inmate search or InmateAid's inmate locator, which searches across California facilities by name.
Booking takes time - sometimes several hours after arrest. If the search comes back empty, wait a few hours and try again before assuming they have been transferred somewhere else. You can also pull their arrest record and booking details to confirm the charges and facility assignment. For the most direct answer, call Contra Costa MDF at 925-335-4600.
Most people booked at Contra Costa MDF appear before a judge within 24 to 48 hours. At that first appearance the judge sets the bail amount - or denies bail - based on the charges, the person's history, and whether they are considered a flight risk.
If bail is set, your family member can be released by paying the full amount or by using a bail bondsman, who typically charges 10 percent of the total as a non-refundable fee. If bail is denied or the amount is unaffordable, they remain at Contra Costa MDF until the case resolves. InmateAid's bail and bond guide walks through every option including what to do if you cannot afford a bondsman.
Right after arrest, your family member goes through intake at Contra Costa MDF - identity verification, medical screening, property inventory, and classification. Classification places them in a housing unit based on the charges, prior record, and intake behavior. It is not a punishment. It is how the facility manages a population that ranges from people picked up on minor warrants to individuals facing serious charges.
For the first 24 to 48 hours, phone access and visitation are typically unavailable while booking completes. Once they are assigned to a housing unit, those channels open up. InmateAid's what happens in jail guide covers the full intake process step by step so you know what to expect.
Your family member calls you - you cannot call them. Calls from Contra Costa MDF go through Global Tel Link (GTL) - ConnectNetwork and all calls are recorded except attorney calls. Set up a Global Tel Link (GTL) - ConnectNetwork account before the first call so the connection goes through without delay.
Phone contact is more important than most people realize going into this. A regular call - even a short one - makes a measurable difference in how someone holds up inside. Do not let the setup friction stop you. Visit InmateAid's jail calls page for step-by-step account setup, current rate information, and tips for keeping funds available.
Visitation hours at Contra Costa MDF are set by the facility and can change without much notice. Before making the trip, call 925-335-4600 to confirm current hours, any advance registration requirements, and what you are allowed to bring.
The most common mistake families make is showing up without confirming first - and that results in a wasted trip and a missed visit for your family member. General rules across most California county jails: dress conservatively, avoid colors that resemble inmate uniforms, leave your phone in your car, and bring valid government-issued ID. Children may be permitted with specific requirements depending on the facility. InmateAid's visitation guide has a full checklist you can run through before you go.
Martinez Detention Facility Visitation - Click here for Visiting Hours
Monday, Tuesday, Wednesday, Saturday, and Sunday:
- 8:30 a.m. - 11:00 a.m.
- 1:00 p.m. - 5:00 p.m.
- 7:30 p.m. - 9:00 p.m.
Thursday:
- 8:30 a.m. - 11:00 a.m.
- 1:00 p.m. - 5:00 p.m.
Friday:
- 7:30 p.m. - 9:00 p.m.
Up to four visitors may visit an inmate at one time and all visitors must be scheduled and enter the facility no later than 30 minutes prior to the end of any visiting block. Registration of scheduled visitors will begin 30 minutes before the posted visiting time. Visitors are required to have their visit slip time stamped and in the tray 30 minutes before their visit.
Social visits will be scheduled only by the inmates. Please refer to Visiting Rules and Regulations for specific guidelines regarding these visits. Custody Services Bureau information posted is for reference only and does not necessarily include a specific policy in its entirety. Custody Services policy is reviewed frequently and is subject to change at any time.
Visiting Rules and Regulations - Each inmate and visitor is responsible for his or her conduct during visits. Any violation of laws, regulations or procedures governing visits may result in termination, suspension, restriction, revocation, arrest, or denial of visiting with the person or persons involved. Visitors may be excluded from visiting activities by the Facility Commander because of prior misconduct. The visiting process is governed by rules and regulations.
Visitors are expected to dress appropriately and maintain a standard of conduct during visiting that is not offensive to others and is consistent to make visiting a safe, positive, and constructive time for families, inmates, and staff.
All regulations of visiting shall be made available to all visitors, staff, and inmates at the time of admission.
The privacy of inmates and their visitors shall be respected subject to the need to verify the identity of an inmate or visitor, enforce laws, regulations, and procedures, and/or ensure the safety of persons and facility security. The Office of the Sheriff may utilize video-recording devices in visiting areas, excluding areas where confidential attorney consultations occur.
Visiting privileges shall be suspended only by order of the Facility Commander, except where the suspension is imposed as part of a formal disciplinary proceeding. Inmates should not be denied access to visits with persons of their choice except when the Facility Commander or designee can present clear and convincing evidence that such visitation jeopardizes the safety and security of the facility or the visitors. The Classification Unit will be notified of all visiting suspensions.
Money on the books - also called the commissary or trust account - gives your family member access to hygiene items, snacks, phone time, and postage. It is one of the most practical things you can do and it has a direct effect on their daily comfort.
Contra Costa MDF accepts deposits through approved channels that typically include online deposit, phone deposit, or a kiosk at the facility. Use your family member's full legal name and booking number exactly as they appear in the jail's system - any error in the name or number will delay or reject the deposit. InmateAid's send money page lists the specific deposit methods accepted at Contra Costa MDF and walks through the process.
A letter or a printed photo costs almost nothing to send and means far more than most people outside appreciate. Contra Costa MDF accepts incoming mail addressed to your family member at 1000 Ward St. Put their full legal name and booking number on every piece of mail.
Standard rules at most California county jails: plain white paper only, no staples, no glitter, no stickers, no colored ink. Photos should be standard print size with nothing written on the back. Mail that does not meet the facility's standards will be rejected - and the facility may not notify you that it was. Keep it simple.
InmateAid's send mail service lets you write and send directly from your phone or computer. We print on approved stock and mail it for you, so rejection for formatting is not a risk.
Books and magazines must come new, ordered directly from the publisher or through an online retailer - not shipped from your home address. Facilities require this to prevent contraband. Order through Amazon or directly from the publisher. Anything shipped from a personal address will be turned away.
County jail procedures, visitation rules, phone rates, inmate search tools, bail processes, and what happens at release all vary by state. California has its own rules and its own agencies, and what applies in one state does not always apply here.
InmateAid's California prison resources hub covers all of it - written specifically for families navigating the California system. Start there when you need answers that go beyond what this facility page covers.
County jail time is hard in a way that is different from anything else. The uncertainty - not knowing how long, not knowing what comes next - wears on everyone. What you can control is the connection. Calls, letters, visits, money on the books. Every one of those things tells your family member that someone out here is paying attention and is not going anywhere.
InmateAid was built for exactly this. Use us.