Agency, MT -- U.S. Census Designated Place in Montana Population (2000): 324 Housing Units (2000): 90 Land area (2000): 8.577370 sq. miles (22.215286 sq. km) Water area (2000): 0.007082 sq. miles (0.018342 sq. km) Total area (2000): 8.584452 sq. miles (22.233628 sq. km) FIPS code: 00587 Located within: Montana (MT), FIPS 30 Location: 48.257148 N, 109.772875 W ZIP Codes (1990): Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Agency, MT Agency