Sanctuary jurisdictions refuse to cooperate with the efforts of Immigration and Customs Enforcement (ICE) to deport illegal aliens. By doing so, they provide sanctuary or refuge for these lawbreakers. Typically, these jurisdictions will not accept ICE “detainers.” i.e., requests not to release offenders until ICE can come and take them into custody for deportation.
During the past four years, sanctuaries have released 22,000 illegal aliens charged with crimes other than violating immigration laws. This total came about through the refusal of around seven percent of all ICE detainers issued during those years.
A study done by ICE in 2015 found that 23 percent of criminals aliens released by sanctuary jurisdictions are re-arrested for new crimes within eight months of their release. The Center for Immigration Studies (CIS) has posted the following list of sanctuary states and localities.
Read more at cis.org