Wellington is a city in and the county seat of Sumner County, Kansas, United States. As of the 2010 census, the city population was 8,172.
Wellington was platted in 1871 and named for the Duke of Wellington. It was designated as the Sumner County seat in 1872, winning out over Sumner City according to the Wellington library. Cattle herders coming up the Chisholm Trail helped to build the early town's economy.
The first post office in Wellington was established in July 1871.
In 1887, the Chicago, Kansas and Nebraska Railway built a north–south branch line from Herington through Wellington to Caldwell. Creditors foreclosed on it 1891 and the railroad was taken over by Chicago, Rock Island and Pacific Railroad, which shut down in 1980 and reorganized as Oklahoma, Kansas and Texas Railroad, merged in 1988 with Missouri Pacific Railroad, merged in 1997 with Union Pacific Railroad. Most locals still refer to this railroad as the "Rock Island".
Wellington is located at 37°16′2″N 97°24′0″W (37.267289, -97.400061), at an elevation of 1230 feet. According to the United States Census Bureau, the city has a total area of 8.19 square miles (21.21 km2), of which, 7.61 square miles (19.71 km2) is land and 0.58 square miles (1.50 km2) is water.
The climate in this area is characterized by hot, humid summers and generally mild to cool winters. According to the Köppen Climate Classification system, Wellington has a humid subtropical climate, abbreviated "Cfa" on climate maps.
As of the 2010 United States Census, there were 8,172 people, 3,246 households, and 2,105 families living in the city. The population density was 1,073.9 inhabitants per square mile (414.6/km2).