Cook is an unincorporated community in Madison Township, Fayette County, Ohio, United States. It is located at 39°40′59″N 83°18′26″W, along Cook-Yankeetown Road (Fayette County Highway 34), just west of its intersection with U.S. Route 62/State Route 3.The Cook Post Office was established on January 20, 1885, but was discontinued on March 31, 1933. The mail service is now sent through the Mount Sterling branch.