Robert Spurrier Ellison (1875-1945) was a prominent Colorado lawyer, businessman, politician, historian, and author.

Robert Spurrier Ellison (1875-1945) was born in Rushville, Indiana. After graduating from Indiana University in 1900, Ellison studied law. He was admitted to the Colorado bar in 1903 and specialized in mining litigation with the Colorado Springs law firm Schuyler and Schuyler. Ellison married Vida F. Gregory of Colorado Springs in 1907.

In 1911, Ellison was elected to the Colorado House of Representatives. He moved to Denver in 1915, and to Casper, Wyoming in 1919. While in Wyoming, Ellison became vice-president of the Midwest Refining Company. He helped to found Wyoming's Historical Landmark Commission and served as regional director of the Oregon Trail Memorial Association. Ellison also compiled and financed a history of the Pawnee nation, for which the Pawnee Supreme Council named him a tribal chief. In 1930, Standard Oil of Indiana bought the Midwest Refining Company and transferred Ellison to Tulsa, Oklahoma.

Ellison returned to Colorado Springs following his retirement in 1940, where he was elected president of the Bank of Manitou, mayor of Manitou Springs and director of the Boy Scouts of the Pikes Peak Region. Ellison wrote several books on the American West, and was considered Colorado's greatest book collector. His Western Americana collection was once said to be the second largest in the United States.

Ellison died at his home in Manitou Springs August 16, 1945.