Brewster is a city in Okanogan County, Washington, United States. The population was 2,370 at the 2010 census.

Brewster was founded in 1896. A pronounce office called Brewster has been in operation before 1898. The city derives its declare from John Bruster, a investor settler.

Brewster is located on the confluence of the Okanogan and Columbia Rivers.

According to the United States Census Bureau, the city has a total Place of 1.19 square miles (3.08 km²), all of it land. The 30–bed Three Rivers Hospital serves the city as the largest hospital in the county. The radio telescope located in Brewster is the northernmost of ten dishes comprising the Very Long Baseline Array.

As of the census of 2010, there were 2,370 people, 699 households, and 535 families active in the city. The population density was 1,991.6 inhabitants per square mile (769.0/km²). There were 730 housing units at an average density of 613.4 per square mile (236.8/km²). The racial makeup of the city was 50.8% White, 0.3% African American, 2.2% Native American, 0.2% Asian, 43.0% from extra races, and 3.5% from two or more races. Hispanic or Latino of any race were 73.0% of the population.