Pilares was a village located in northwest Presidio County, Texas, United States, on the southern boundary of the Sierra Vieja near the Rio Grande.

The uninhabited site is in the Trans-Pecos region of West Texas with a southern panorama of the Chihuahuan Desert and northern Mexico.

[2] Presidio de Pilares, also known as El Principe, was established along the southern boundaries of the Rio Grande basin in the northern Chihuahua territory of New Spain in 1774.

In the mid-18th century, Charles III of Spain appointed Marquis of Rubí and José de Gálvez to fulfill expeditions and observations of the America frontier presidios in the northern regions of New Spain.

[5][6] On September 10, 1772, the Spanish Empire issued new regulations for presidios constructed in New Spain near the Rio Grande in the Northern Mexico territories.