Somersworth, New Hampshire, United States [City]; population was 11,249 in 1990; housing units was 4,719 in 1990; location is 43°15'N 70°53'W; land area is 9.78 square miles (6,260 acres); water area is 0.23 square miles (147 acres); FIPS code is 69940 [SourceCBP]