Located on part of a Spanish land grant known as Llano Grande, Weslaco was founded in 1919 by a partnership composed of R. C. , Dan, and Ed Couch and Robert L. Reeves. The city's name is take from the initials of the W. E. Stewart Land Co. , which held title to the site from 1917 to 1919. Weslaco had a post office by 1920 and was incorporated in 1921. Founded nearly ten years after most other valley cities in the area, Weslaco depends on a wide variety of businesses for its economic base. Descendants of some of the early settlers still live here.