Colfax is the county seat of Whitman County, Washington, United States.
The population was 2,805 at the 2010 census. The population is estimated at 2,911 per the State of Washington Office of Financial Management in 2018 making Colfax the second largest city in Whitman County behind Pullman. It is situated amidst wheat-covered hills in a valley at the confluence of the north and south forks of the Palouse River. U.S. Route 195, which forms the town’s main street, intersects subsequent to State Route 26 at the north decline of town; in the past, Colfax as well as lay at the junction of three major railway lines. It was named after Schuyler Colfax, the vice president from 1869–73.

Palouse Indians were the first known human inhabitants of the Colfax area. White settlers arrived in the summer of 1870, and soon built a sawmill. A flour mill and additional businesses followed, and Colfax soon grew into a prosperous town. Originally, pioneer citizen James Perkins called the settlement “Belleville” in honor of his girlfriend; when he found a new love, he misused the town’s publicize to Colfax, for vice president Schuyler Colfax.

Colfax was officially incorporated upon November 29, 1873. In 1889–90, the town vied like several other finalists to become the site of a further state agricultural college, present-day Washington State University. The praise ultimately fell to simple Pullman, fifteen miles (25 km) southeast.

The into the future history of Colfax was marred by prominent lynchings in 1894 and 1898. The city incurred significant flooding in 1910 in beforehand March.

Until passed by Pullman at the 1930 census, Colfax was the largest city in the county.