Rosalia is a town in Whitman County, Washington, United States.

It is an agricultural community in the Palouse region, at an elevation of 2,238 feet (682 m) above sea level.

[4] Rosalia was the site of an 1858 Battle of Pine Creek between United States troops, including Nez Perce allies, under Brevet Lieutenant Colonel Edward Steptoe, and members of the Coeur d'Alene, Palus and Spokane Native American tribes.

According to the United States Census Bureau, the town has a total area of 0.62 square miles (1.61 km2), all of it land.

There were 270 housing units at an average density of 435.5 per square mile (168.1/km2).

27.6% of all households were made up of individuals, and 14.1% had someone living alone who was 65 years of age or older.

28.9% of all households were made up of individuals, and 13.0% had someone living alone who was 65 years of age or older.