Ninomiya is located on the coast of west-central Kanagawa Prefecture, bordered to the south by Sagami Bay of the Pacific Ocean.

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

[2] Per Japanese census data,[3] the population of Ninomiya peaked around the year 2000 and has declined slightly since then.

Ninomiya has a mayor-council form of government with a directly elected mayor and a unicameral town council of 14 members.

In terms of national politics, the town is part of Kanagawa 15th district of the lower house of the Diet of Japan.