Colhoun, was born in Staunton, Virginia, where he attended common schools before graduating from the College of New Jersey (now Princeton University) in 1774.

Colhoun married Floride Bonneau a member of a prominent Charleston, South Carolina Huguenot family.

Charles Drayton's company of volunteer militia for service in the Revolution at its organization in Charleston, South Carolina.

After the war, in 1783, he studied law and was admitted to the bar and commenced practice in Charleston, South Carolina, working mostly in estate settlements and personal injury suits.

He was elected as a Democratic-Republican to the 7th United States Congress as a senator, serving from March 4, 1801, until his death on October 26, 1802, in Pendleton, South Carolina.