Alder, MT -- U.S. Census Designated Place in Montana Population (2000): 116 Housing Units (2000): 69 Land area (2000): 2.013323 sq. miles (5.214482 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 2.013323 sq. miles (5.214482 sq. km) FIPS code: 00850 Located within: Montana (MT), FIPS 30 Location: 45.324531 N, 112.108035 W ZIP Codes (1990): Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Alder, MT Alder