This La Salle County seat lies on I-35 in the northwestern part of the county. It was named for Joseph Cotulla, a Polish immigrant, who established the town site upon learning that the International-Great Northern Railroad was extending its railroad line through La Salle County. Its economy was largely based on cattle ranching. In the early 1900s the county grew in population and became the "Winter garden" area, growing winter season vegetables for the northern market. As time passed, water became scarce, and the land converted to a hunting economy. In 2011, Shale gas was discovered and the town has doubled in size.