Incarceration of any kind is designed to be an unpleasant experience. But, the policies, rights, and daily life of an inmate can be very different between these two types of institutions. So, what is the difference between jail and prison. At the most basic level, the fundamental difference between jail and prison is the length of stay for inmates. Think short-term and long-term. Jails are usually run by local law enforcement and/or local government agencies, and are designed to hold inmates awaiting trial or serving a short sentence.