On December 21, the Department of Homeland Security released the Alien Incarceration Report for Fiscal Year 2017. The report discloses the number of confirmed and suspected foreign-born inmates in the custody of the federal prison system, which includes the Bureau of Prisons (BOP) and the U.S. Marshals Service (USMS).

DHS reported a total of 58,766 "known or suspected" aliens in the custody of federal authorities. According to the Federal Bureau of Prisons, there are 184,379 total federal inmates, meaning that almost 32 percent of all federal inmates are aliens. The number of aliens in federal custody has risen since the last report: At that time, the Justice Department estimated that there were 42,000 aliens, representing 24 percent of the federal prison population.

Of the 58,766 "known or suspected" aliens, ICE could confirm that 37,557 (64 percent) are confirmed aliens, defined as meaning that they are non-citizens and foreign-born. From that group of 37,557 ICE-confirmed aliens, an astonishing 35,334 (94 percent) were illegally residing in the United States.

Prisoners known or suspected to be aliens are reviewed by ICE to determine their immigration status, and are placed into one of five categories:

Under Investigation: Further investigation by ICE is required to confirm alienage and establish potential removability In Proceedings – Legal: Confirmed alien who is lawfully present in the United States, but has been charged as a removable alien; removal proceedings are ongoing In Proceedings – Illegal: Confirmed alien who is unlawfully present in the United States; removal proceedings are ongoing Subject to Final Order of Removal: Confirmed alien who is subject to a final order of removal Relief/Benefit: Confirmed alien who has been granted relief or protection from removal that would generally be considered lawful status

Of the known and suspected aliens under investigation by ICE, the vast majority (31,699) are confirmed as illegal aliens and awaiting removal from the country or are still under investigation (21,209).

Immigration courts found that only 10 aliens qualified for relief and will not face removal proceedings.

Open-borders advocates and the mainstream media frequently make the claim that aliens are less likely to commit crimes (see here, here, here, and here, for example). This data casts doubt on that assertion. Many of the aliens in federal custody are held for immigration violations, but that does not diminish the fact that a full 32 percent of federal prisoners are aliens, and that over 90 percent of those are in the country illegally.

As my colleague Jessica Vaughan wrote earlier this year:

These statistics ... confirm what every law enforcement agency in America already knows: Border security and immigration enforcement serve an important public safety function and cooperation between state, local, and federal law enforcement officers is essential to ensuring that deportable criminal aliens are removed from the country instead of released back into our communities. Further, these statistics undercut the argument of sanctuary policy proponents who argue that immigrants are more law-abiding than Americans and that they do not contribute to crime problems in our communities.

Those concluding remarks ring true for this same release.