William Greyer Coop (February 26, 1805 – June 4, 1874) was a farmer and settler from Illinois and Iowa, who served as a colonel of the militia, a sheriff and a member of the legislatures of Iowa Territory and the State of Iowa.[1] He was born in Greene County, Virginia, and successively lived in Tennessee, Washington County, Pennsylvania, Wabash County, Indiana, and Macoupin County, Illinois, where he was county sheriff, before moving to Iowa.[2]