Here are some resources that I have found helpful:
A 2015 Child Trends report focusing on children with incarcerated parents
The Bureau of Justice Statistics website, which has lots of information about correctional populations, including midyear reports
The U.S. federal government’s website on children with incarcerated parents
Arrest protocols to safeguard children
The Urban Institute’s portfolio regarding children with incarcerated parents
Parenting Inside Out, the most rigorously evaluated parenting program for incarcerated parents
Sesame Street’s Little Children, Big Challenges: Incarceration toolkit
A national database about and for incarcerated parents and their families; although much of the information is accurate, some of the fact sheets are outdated and some of the information is not research-based