'Jefferson County, MT' definitions:

Jefferson -- U.S. County in Montana

From: Gazetteer 2000
Name :
Jefferson -- U.S. County in Montana
Population (2000) :
10049
Housing Units (2000) :
4199
Land area (2000) :
1656.636326 sq. miles (4290.668205 sq. km)
Water area (2000) :
2.193259 sq. miles (5.680515 sq. km)
Total area (2000) :
1658.829585 sq. miles (4296.348720 sq. km)
Located within :
Montana (MT), FIPS 30
Location :
46.119657 N, 112.117726 W