Large sections of the city were destroyed by the 2011 Tōhoku earthquake and tsunami and major fires on March 11, 2011.

The city wraps around the western part of Kesennuma Bay and also includes the island of Ōshima.

Its deeply indented rias coastline forms the southern boundary of the Sanriku Fukkō National Park, which stretches north to Aomori Prefecture.

The island of Ōshima and its 3,000 residents, included in the city limits, was isolated by the tsunami which damaged the ferry connections.

[6] After the tsunami, spilled fuel from the town's fishing fleet caught fire and burned for four days.

[8] In August 2013, residents decided to scrap a fishing boat - the Kyotoku Maru No 18 - which was swept inland by a giant wave during the 2011 tsunami.

[10] Kesennuma has a mayor-council form of government with a directly elected mayor and a unicameral city legislature of 24 members.

In terms of national politics, the city is part of Miyagi 6th district of the lower house of the Diet of Japan.