'Allegheny County, PA' definitions:

Allegheny -- U.S. County in Pennsylvania

From: Gazetteer 2000
Name :
Allegheny -- U.S. County in Pennsylvania
Population (2000) :
1281666
Housing Units (2000) :
583646
Land area (2000) :
730.169813 sq. miles (1891.131054 sq. km)
Water area (2000) :
14.537638 sq. miles (37.652307 sq. km)
Total area (2000) :
744.707451 sq. miles (1928.783361 sq. km)
Located within :
Pennsylvania (PA), FIPS 42
Location :
40.440569 N, 79.959705 W