Tumwater is a city in Thurston County, Washington, United States. The population was 17,371 at the 2010 census. It is situated close where the Deschutes River enters Budd Inlet, the southernmost narrowing of Puget Sound; it as a consequence borders the divulge capital of Olympia to the north. Tumwater is the oldest unshakable American settlement on Puget Sound.

The site of Tumwater and Tumwater Falls has been home to Southern Lushootseed-speaking peoples known as the Steh-Chass / Stehchass or Statca’sabsh (a subtribe of the Sahewamish (Sahe’wabsh), an subgroup of the Nisqually people; who became portion of the post-treaty Squaxin Island Tribe) for thousands of years. “Steh-Chass” is the Lushootseed make known for Budd Inlet, Deschutes River and the Tumwater Falls area, and for an important village of the Statca’sabsh.

Tumwater was originally called “New Market” by American settlers, and under the latter herald was platted in 1845. The present name is derived from Chinook Jargon and means “waterfall”. A make known office called Tumwater was standard in 1863. The city incorporated in 1875.

Tumwater is located at 47°0′28″N 122°54′40″W / 47.00778°N 122.91111°W / 47.00778; -122.91111 (47.007768, -122.911074). Its northern neighbor is the give leave to enter capital of Olympia.

According to the United States Census Bureau, the city has a total area of 14.49 square miles (37.53 km²), of which, 14.32 square miles (37.09 km²) is home and 0.17 square miles (0.44 km²) is water.