Samuel Danford Nicholson (1859 – March 24, 1923) was a United States senator from Colorado.

Samuel Danford Nicholson
United States Senator from Colorado
In office March 4, 1921 – March 24, 1923
Preceded by	Charles S. Thomas
Succeeded by	Alva B. Adams
Personal details
Born	(1859-02-22)February 22, 1859 Springfield, Prince Edward Island, Province of Canada
Died	March 24, 1923(1923-03-24) (aged 64) Denver, Colorado, U.S.
Political party	Republican

Nicholson was born on Feb. 22, 1859 in Springfield, Prince Edward Island, British North America, he attended the public schools there and moved to Michigan and then to Nebraska and later, in 1881, to Leadville, Colorado.

Nicholson became interested in mining, and advanced from miner to foreman, superintendent, manager, and then president of the Western Mining Company. He discovered the zinc ore that bears his name, Nicholsonite.

From 1893 to 1897, Nicholson was the Populist mayor of Leadville; he moved to Denver in 1902. In 1914 and 1916, he was an unsuccessful candidate for governor. During the First World War, he served as State chairman of the Liberty Loan and Victory loan campaigns, and was a member of the United States Fuel Administration. He was elected as a Republican to the United States Senate and served from March 4, 1921, until his death in Denver on March 24, 1923. His interment was in Fairmount Cemetery in Denver.