The Harlem Courthouse at 170 East 121st Street on the corner of Sylvan Place – a remnant of the former Boston Post Road[4] – in the Harlem neighborhood of Manhattan, New York City, was built in 1891-93 and was designed by Thom & Wilson in the Romanesque Revival style.

The brick, brownstone, bluestone, granite and terra cotta building features gables, archways, an octagonal corner tower and a two-faced clock.

In 1936, during the New Deal, Federal Art Project artist David Karfunkle painted a mural, "Exploitation of Labor and Hoarding of Wealth" on its third floor.

[5][6][7] The city government used the building as a laboratory to measure air pollution.

[8] The building was designated a New York City landmark in 1967, and was added to the National Register of Historic Places in 1980.