It faces the Pacific Ocean to the east and its coastline is a typical ria coast with several good natural harbors.

In particular, the port of Katsuura is located in a cove protected by the island of Nakanoshima at its entrance, so it is not affected by rough waves from the sea.

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

[citation needed] Nachikatsuura has a mayor-council form of government with a directly elected mayor and a unicameral city council of 10 members.

In terms of national politics, the town is part of Wakayama 3rd district of the lower house of the Diet of Japan.

Kinki University's Fisheries Research Institute, Uragami Experiment Station and its Aquatic Culture Seedling Center are located in Nachikatsuura.