This community was developed with the building of the Orient Railroad in 1911. It served as a marketing and retail center for surrounding cattle and sheep ranches. The University of Texas owned much of the arid grazing land around Big Lake where, in 1923, a large oil pool was discovered with the Santa Rita No. 1 well. The discovery made The University of Texas one of the richest schools in the nation. Today, Big Lake is the seat of Reagan County. The name was derived from a large depression to the south that forms a broad, shallow lake during rare wet seasons.