Gray Summit is a census-designated place (CDP) in Franklin County, Missouri, United States. The population was 2,640 at the 2000 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, Missouri and Kansas City, Missouri; a railroad tunnel runs underneath the community. It is located on Interstate 44 and is home to Purina Farms and the Shaw Nature Reserve.