'Prince William' definitions:

Prince William -- U.S. County in Virginia

From: Gazetteer 2000
Name :
Prince William -- U.S. County in Virginia
Population (2000) :
280813
Housing Units (2000) :
98052
Land area (2000) :
337.783520 sq. miles (874.855263 sq. km)
Water area (2000) :
10.578952 sq. miles (27.399358 sq. km)
Total area (2000) :
348.362472 sq. miles (902.254621 sq. km)
Located within :
Virginia (VA), FIPS 51
Location :
38.695694 N, 77.409773 W