List of law enforcement agencies on Long Island

The List of Long Island law enforcement agencies provides an inclusive list of law enforcement agencies serving New York's Long Island.

This includes those agencies serving the New York City boroughs of Brooklyn and Queens on the western portion of Long Island along with those serving the suburban counties of Nassau County and Suffolk County.

Each of the five counties of New York City — New York (Manhattan), Bronx, Richmond (Staten Island), Kings (Brooklyn) and Queens — had a county sheriff's office.

In 1942 they were merged to form the New York City Sheriff's Office.

In 1939, the corrections part of the each county sheriff's office separated and became the consolidated New York City Department of Correction.