[2] Umaji is located in a mountainous region in northeastern Kōchi Prefecture on the island of Shikoku.

During the Edo period, the area was part of the holdings of Tosa Domain ruled by the Yamauchi clan from their seat at Kōchi Castle.

The village has been on the verge of merging with nearby municipalities, but it has retained a strong sense of independence.

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

Umaji, together with the other municipalities of Aki District, contributes one member to the Kōchi Prefectural Assembly.

In terms of national politics, the village is part of Kōchi 1st district of the lower house of the Diet of Japan.

As well as two hot springs and several campsites, Umaji has a forest train, craft workshops, a village tour and other tourist activities.