El Fuerte de Santa Cruz del Cíbolo, also called El Fuerte de Santa Cruz, El Fuerte del Zívolo, El Fuerte del Cíbolo, Arroyo del Cíbolo, or simply El Cíbolo, was an eighteenth-century Spanish fort that existed from 1734 to 1737 and again from 1771 to 1782. It was built to protect the many Spanish ranchos that belonged to missions and private individuals between Bexar and La Bahía. From the time when San Antonio was first established, its presidio, missions, and settlers were subjected to constant raids upon their livestock by Indians, mainly Apaches. In order to stop these depredations, Governor Manuel de Sandoval, who took office in 1734, decided to strengthen the garrison at San Antonio with extra soldiers from Los Adaes, La Bahía, and the Rio Grande and to protect the presidial horses by moving them to a secluded site on Arroyo del Cíbolo about sixteen leagues southeast of San Antonio. But the early attempt to establish this fort, at this time called Arroyo del Cíbolo or El Cíbolo, failed after three years, and after two Apache raids in 1737, both the garrison and the horses were moved back to San Antonio.
The reestablishment of the fort in 1771 was a direct result of the readjustments made in Spanish colonial policy in the northern provinces of New Spain after the Seven Years' War, 1756–63. The Marqués de Rubí's inspection of 1766–68 resulted in the Reglamento é instrucciones para los presidios que han forman en la linea de frontera de la Nueva España by King Carlos III on September 10, 1772, commonly called the Royal Regulations or New Regulations for Presidios, which authorized the building of fifteen presidios in a line from the Gulf of California to the Gulf of Mexico. Included in this arrangement was the re-establishment of El Fuerte del Cíbolo with a detachment of twenty-one men. Official sanction for the fort, however, did not have to wait for the Royal Regulations of 1772, for out of sheer necessity it had already been established by Governor Barón de Ripperdá on April 12, 1771. Lipan Apache raids had forced the abandonment of numerous farms and ranches of the missions and settlers in El Rincón, the Spanish name for the wedge of land between the San Antonio River and Cibolo Creek. This prompted Governor Ripperdá to reestablish the post of El Fuerte del Cíbolo to protect the seventeen ranches therein. Writing to the viceroy on April 12, 1771, Ripperdá declared that there were fifty men stationed at the new post, which was being constructed with a good stockade. On June 7, 1771, he wrote that the fort was nearly completed and that while some of the men stayed at the fort to do the work, others were out reconnoitering tracks of Indians. Official sanction for the fort as authorized by the Royal Regulations was received by Governor Ripperdá on May 18, 1773.
In appearance, El Fuerte del Cíbolo was "a little stockade fort in the place" where nearby ranchers who wanted the shelter of the fort could build their jacals. The site was at the natural ford on Cibolo Creek halfway between Béxar and La Bahía, a place known by local residents as Carvajal Crossing (where present Farm Road 887 crosses Cibolo Creek in Karnes County). There the fort continued to protect the ranches of the area for about ten years. Soldiers from the fort were sent out on scouting expeditions and had many engagements with hostile Indians. With the establishment of a monthly mail system in Texas in 1779, soldiers of Fort Cíbolo would relay the mail between Presidio La Bahía and Presidio San Antonio de Béxar. Twenty soldiers were stationed in El Fuerte del Cíbolo on the significant day of July 4, 1776. Some of these helped escort Texas cattle and horses to the Spanish forces of Gen. Bernardo de Gálvez, who defeated the British in Louisiana and Florida, thereby contributing to the winning of the American Revolution. After a directive of Commandant-General Teodoro de Croix dated January 12, 1782, El Fuerte del Cíbolo was abandoned and destroyed in March 1782. There are no physical remains of the fort, the site of which is on private property inaccessible to the public. On May 4, 1991, an official state historical marker to commemorate the fort was placed and dedicated in front of the Church of the Nativity of the Blessed Virgin Mary at Cestohowa, 2½ miles south of the fort site.