Ōmachi (大町町, Ōmachi-chō) is a town located in Kishima District, Saga Prefecture, Japan.

[3] The total area of the town is 11.50 km2 (4.44 sq mi) Ōmachi is located about 20 kilometers inland west of Saga City.

Saga Prefecture Ōmachi has a humid subtropical climate (Köppen Cfa) characterized by warm summers and cool winters with light to no snowfall.

Ōmachi has a mayor-council form of government with a directly elected mayor and a unicameral town council of eight members.

In terms of national politics, the town is part of the Saga 2nd district of the lower house of the Diet of Japan.