Subsequently, O'Neil, who originally owned a fourth of the section of the township, purchased the interests of McConnell and Swearingen, and retained sole ownership of the land.

The 1890 census showed 357 inhabitants across the county, with 89 ranches and farms and 335 acres (1.36 km2) of land in cultivation.

The proposed town of Wellington was located on the land owned by Ernest T. O'Neil who was promoting this location, and had been given its proposed name by his wife, Matilda Anna Elisabeth "Lizzie" O'Neil, who greatly admired the Duke of Wellington, hero of the Battle of Waterloo.

In September 1890, the vote was held and Wellington was selected for the seat of the newly organized county of Collingsworth.

In 1891 the new city, laid out by Ernest T. O'Neil, was surveyed and platted, and the first postal service and postmaster, Carrie M. Barton, was established on January 9, 1891.

This became the first mercantile store and commercial building in Wellington, prior to the opening of a two-story hotel by O'Neil.

Later O'Neil organized the first bank, was active in all phases of the county's growth and development, and served as postmaster from August 22, 1895 to December 11, 1897.

With the location as "Wellington, Texas", the story tells of their wrecking their car, terrorizing a family and shooting the daughter-in-law (but actually their daughter), kidnapping two law enforcement officers and taking them in their car near Erick, Oklahoma, where the two kidnapped men were tied to a tree with barbed wire cut from a fence.

According to the United States Census Bureau, Wellington has a total area of 1.4 square miles (3.5 km2), all land.