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