Duncan, MS -- U.S. town in Mississippi Population (2000): 578 Housing Units (2000): 186 Land area (2000): 0.931242 sq. miles (2.411906 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 0.931242 sq. miles (2.411906 sq. km) FIPS code: 20380 Located within: Mississippi (MS), FIPS 28 Location: 34.042147 N, 90.746669 W ZIP Codes (1990): 38740 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Duncan, MS Duncan