Colusi originates from the local Coru Native American tribe, who in the 1840s lived on the opposite side of the Sacramento River.

In 1850, Charles D. Semple purchased the Rancho Colus Mexican land grant on which Colusa was founded and called the place Salmon Bend.

The California legislature changed the town's (and the county's) name to Colusa in 1854.

The town flourished due to its location on the Southern Pacific Railroad.

[5] According to the United States Census Bureau, the city has a total area of 1.8 square miles (4.7 km2), all of it land.

Colusa features a historic Chinatown, Carnegie Library building constructed in 1905, and an architecturally noteworthy courthouse built in a classical style, among its historically notable buildings.

[6] During December 1996–January 1997, the nearby Colusa Weir Gauge reached flood stage.

This historic flooding event devastated the region by destroying thousands of crop acres (rice, tomatoes, alfalfa) and property.

The Colusa Weir Gauge reached flood stage 68.67 feet (20.93 m) on January 3, 1997.

Colusa County industry is dominated by agriculture, primarily in rice crops and tree nuts like almonds and walnuts.

It's one of the top rice producing counties in the United States with over 135,000 acres harvested in 2016.

[18] Federally, Colusa is in California's 3rd congressional district, represented by Republican Kevin Kiley.

Starting in the 2011–12 academic year, the name of the high school mascot was changed from the Redskins to the Redhawks amid controversy over using names and insignia deemed derogatory toward Native Americans.