In many institutions will allow inmates to marry. There are some criteria, one being that they must have a sentence longer than one year. Call the facility chaplain for details. What legal process applies is related to the rules of the place where the person is incarcerated, the terms of their sentence, practicalities, etc. The laws applicable to marriage however, are no different for someone who is in jail versus someone who is not. The Supreme Court recognized marriage as a fundamental right in Loving v. Virginia, and further confirmed that prisoners maintain that right behind bars in the Turner v. Safley decision. Reasons for marrying an inmate, beyond the personal, might have to do with wills or estate planning, taxes, or “intimate” time with your inmate. However, only three state prison systems — California, Washington and New York — still permit some conjugal visits for spouses.