Susami is located in the southern portion of Kii Peninsula, and faces the Pacific Ocean to the west.

Wakayama Prefecture Susami has a Humid subtropical climate (Köppen Cfa) characterized by warm summers and cool winters with light to no snowfall.

After the Meiji restoration, the area became part of Nishimuro District, Wakayama, and the village of Sasami (周参見) was established with the creation of the modern municipalities system on April 1, 1889.Susami was raised to town status on February 11, 1924.

On March 31, 1955, Susami annexed the neighboring villages of Samoto and Otsugawa and changed the spelling of its name from kanji to hiragana.

Susami has a mayor-council form of government with a directly elected mayor and a unicameral town 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.

Forestry such as cedar and cypress is traditionally practiced in inland areas, but has stagnated since the mid-1960s due to high costs and low domestic demand.