What is "thermopolis"

Population (2000): 3172
Housing Units (2000): 1568
Land area (2000): 2.383214 sq. miles (6.172495 sq. km)
Water area (2000): 0.085464 sq. miles (0.221352 sq. km)
Total area (2000): 2.468678 sq. miles (6.393847 sq. km)
FIPS code: 76515
Located within: Wyoming (WY), FIPS 56
Location: 43.645667 N, 108.214641 W
ZIP Codes (1990):
Note: some ZIP codes may be omitted esp. for suburbs.
Headwords: