Thomas Koon House is a historic home in Cumberland, Allegany County, Maryland, United States. It is a brick Prairie-style house of large scale built in about 1912. It features arranged rectangular blocks with large expanses of window space, a terra cotta tiled hip roof and a small similarly influenced detached garage. The house was designed by Holmboe & Lafferty of Clarksburg for Doctor Thomas W. Koon, who arrived in Cumberland setting up an "active general practice" in May 1900.