Alexander Hamilton Sibley (October 17, 1817-July 10, 1878) was the president of the Silver Islet Mining Company which operated a silver mine in Ontario.
He was born in Detroit in 1817, the son of the first mayor of Detroit, Solomon Sibley. He was the brother of the first governor of Minnesota, Henry Hastings Sibley.
From 1870 until his death in 1878, Sibley lived in Detroit and spent his summers at the mine. He died in New York City in 1878.