Harlem is an unincorporated community in Winnebago County, in the U.S. state of Illinois.

[2] Harlem is the closest city to Rock Cut State Park.

A post office called Harlem was established in 1839, and remained in operation until it was discontinued in 1928.

[5] Harlem Cemetery was built on a piece of land donated by one of the first citizens of the town, Asa Taylor, who is buried there.

[6] RMTD provides bus service on Route 20 connecting Harlem to destinations throughout the Rockford area.