'Great Falls, VA' definitions:

Great Falls, VA -- U.S. Census Designated Place in Virginia

From: Gazetteer 2000
Name :
Great Falls, VA -- U.S. Census Designated Place in Virginia
Population (2000) :
8549
Housing Units (2000) :
2852
Land area (2000) :
17.866809 sq. miles (46.274822 sq. km)
Water area (2000) :
0.040996 sq. miles (0.106179 sq. km)
Total area (2000) :
17.907805 sq. miles (46.381001 sq. km)
FIPS code :
32496
Located within :
Virginia (VA), FIPS 51
Location :
39.001609 N, 77.283249 W
ZIP Codes (1990) :
22066
Note :
some ZIP codes may be omitted esp. for suburbs.