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 first surveyed on April 4, 1871 and named for the Duke of Wellington. It was designated as the permanent seat of Sumner County in 1872, winning out over competitor Sumner City. Trading with the cattle herds coming up the Chisholm Trail was an important factor in the early economy of the town.
In 1887, the Chicago, Kansas and Nebraska Railway built a branch line north-south from Herington through Wellington to Caldwell. It foreclosed in 1891 and taken over by Chicago, Rock Island and Pacific Railway, 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".