'Powder River' definitions:

Powder River, WY -- U.S. Census Designated Place in Wyoming

From: Gazetteer 2000
Name :
Powder River, WY -- U.S. Census Designated Place in Wyoming
Population (2000) :
51
Housing Units (2000) :
44
Land area (2000) :
5.912713 sq. miles (15.313856 sq. km)
Water area (2000) :
0.049661 sq. miles (0.128622 sq. km)
Total area (2000) :
5.962374 sq. miles (15.442478 sq. km)
FIPS code :
62305
Located within :
Wyoming (WY), FIPS 56
Location :
43.034720 N, 106.990626 W
Note :
some ZIP codes may be omitted esp. for suburbs.

Powder River -- U.S. County in Montana

From: Gazetteer 2000
Name :
Powder River -- U.S. County in Montana
Population (2000) :
1858
Housing Units (2000) :
1007
Land area (2000) :
3297.177652 sq. miles (8539.650552 sq. km)
Water area (2000) :
0.759052 sq. miles (1.965936 sq. km)
Total area (2000) :
3297.936704 sq. miles (8541.616488 sq. km)
Located within :
Montana (MT), FIPS 30
Location :
45.363372 N, 105.625006 W