Gray Summit is an unincorporated community and census-designated place (CDP) in Franklin County, Missouri, United States. The population was 2,701 at the 2010 census. Also called "Gray's Summit", it was founded by Daniel Gray of New York, who built a hotel here in 1845. This community was the highest point on the Missouri Pacific Railroad between St. Louis and Jefferson City, Missouri; a railroad tunnel runs underneath the community. It is located on Interstate 44 and is home to Purina Farms, the Shaw Nature Reserve and Point Labaddie Brewery.