For Jail populations (as opposed to prisons), plus convictions, juveniles in the system etc. Washington's Office of Financial Management has a pretty flexible set of data tools, including chart and map visualizations by county, downloadable tables in Excel or SAS format, and data dictionary of sorts.
The down side is that the latest data they have is almost 2 years old
STATE: WA DATASET: Incarceration URL: https://data.wa.gov/Public-Safety/Criminal-Justice-Data-Book/ixek-wnci
DESCRIPTION/COMMENTS:
For Jail populations (as opposed to prisons), plus convictions, juveniles in the system etc. Washington's Office of Financial Management has a pretty flexible set of data tools, including chart and map visualizations by county, downloadable tables in Excel or SAS format, and data dictionary of sorts. The down side is that the latest data they have is almost 2 years old