This document provides information on researching criminal records to find ancestors who may have been incarcerated. It discusses different types of records like prison records, court records, and newspapers that can contain details on crimes, trials, and incarcerations. Specific record collections are mentioned for the federal Bureau of Prisons, as well as state prisons in Louisiana, Washington, Georgia, Connecticut, Tennessee, and Pennsylvania that may hold records dating back to the late 1800s. Tips are provided on distinguishing between prison and jail records and using other sources like census, photos, and genealogical websites.