Dayton is a city in Hennepin and Wright counties in the U.S. state of Minnesota. The population was 4,699 at the 2000 census. Dayton is mainly in Hennepin County, but a part of the city extends into Wright County as well. It is the northernmost city in Hennepin County. The city of Dayton, platted in 1855, is named for city founder, Lyman Dayton (1810-1865). Through his energy and finances, Lyman Dayton was instrumental in bringing the railroad into Minnesota and development of the Lake Superior and Mississippi Railroad, of which he was President until 1865.