Physical contact during prison visits is allowed in most facilities but within limits that vary by security level and individual facility policy.
The standard in most state and federal prisons is a brief embrace and kiss on arrival and another when the visit ends. That contact is generally accepted across custody levels as long as it is brief and appropriate. Extended physical contact or anything that draws staff attention is where things get cut off.
Hand-holding during the visit itself is more of a gray area. Some facilities permit it, others do not, and within the same facility different officers may respond differently. Reading the room and the officer on duty is part of managing visitation. Being respectful and low-profile goes a long way.
The higher the security level, the stricter the contact rules tend to be. Maximum-security facilities may limit contact entirely to the handshake or brief embrace on entry and exit. Minimum-security and camp settings are often more relaxed. County jails frequently have non-contact visitation through glass, which eliminates physical contact regardless of the relationship.
Before making a long trip, call the specific facility and ask about their current visitation contact policy. It is the only way to know exactly what applies at that location.