See our explainers about how redistricting works and why counting less than 1% of the U.S. population in the wrong place has such a significant effect:
After the in the 2000 and 2010 redistricting cycles, we analyzed 37 states, district by district, to determine the problems caused by the Census Bureau's method of counting people in prison:
Research in other states is ongoing. Where full district analyses are not yet available for your state, see our report: Fixing prison-based gerrymandering after the 2010 Census: A 50 state guide.