There is a chart here that is helpful in understanding the total number of people who are impacted by different parts of the criminal justice system. Approx 70% of people in local jails are there for non-violent offenses, approx 45% of people in state prisons are there for non-violent offenses and approximately 94% of people in the federal system are there for non-violent offenses. https://www.prisonpolicy.org/reports/pie2018.html
In the US, jails and prisons are two different things. Prisons are state and federal facilities for criminals convicted of serious crimes with sentences of more than a year. Jails are local facilities for suspects waiting for trial, and those convicted of minor crimes with sentences less than a year.
Another big difference between jail and prison is that a prison sentence must be served as a single, unbroken stay. A jail sentence in many places can be served weekends.