Catasauqua is a borough in Lehigh County, Pennsylvania, settled in 1805 and chartered as a borough in 1853. Catasauqua is a suburb of Allentown, Pennsylvania in the Lehigh Valley region of the state.
Historically, manufacturing was Catasauqua's principal industry, and, in 1839, it was the location of the first manufactured anthracite iron in the nation. Catasauqua's population in 1910 was 5,250. The population was 6,588 at the 2000 census. The word Catasauqua is shortened to "Catty" in local dialect when speaking of the place.
Catasauqua is located at 40°39′11″N 75°28′3″W / 40.65306°N 75.4675°W / 40.65306; -75.4675 (40.652995, -75.467627). Nearby large communities include Allentown three miles (5 km) to the south and Bethlehem.