
Thomas J. Dart (born May 25, 1962) is an American politician and police official. He is the Sheriff of Cook County, Illinois since 2007. A Democrat, he is the chief executive of the second largest such department in the United States after Los Angeles.
Dart was a member of the Illinois Senate from 1991 to 1993. From 1993 to 2003, he was a member of the Illinois House of Representatives.
Dart was the Democratic nominee for state treasurer of Illinois but lost to incumbent Republican Judy Baar Topinka.
Dart, who studied at Loyola University, lives in Mount Greenwood, Chicago.