Irwin, PA -- U.S. borough in Pennsylvania Population (2000): 4366 Housing Units (2000): 2277 Land area (2000): 0.882555 sq. miles (2.285807 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 0.882555 sq. miles (2.285807 sq. km) FIPS code: 37208 Located within: Pennsylvania (PA), FIPS 42 Location: 40.327169 N, 79.702006 W ZIP Codes (1990): Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Irwin, PA Irwin