The Ronquillo land grant, 225 leagues now part of Presidio, Brewster, and Jeff Davis counties, would never have become historically important if John W. Spencer had not discovered silver there in 1880. Spencer and his three partners bought the land around his strike in the Houston and Texas Central Railway company survey, Presidio County, from the state of Texas on November 16, 1885. The partnership later sold its claim to the Presidio Mining Company, which operated the Presidio Mine at Shafter. The Presidio Mine produced more than 32.6 million ounces of silver between 1883 and 1942. Several claimants arose to assert rights to the land on which the silver was located. Central to their claims was the Ronquillo grant, which had been issued conditionally to José Ygnacio Ronquillo in 1832. Although Ronquillo began to fulfill the requirements of his grant, his military service forced him to move. He petitioned the alcalde of Presidio del Norte, Cesario Herrera, to waive the restrictions on his grant, since he had to leave for military reasons. Herrera provided him with a certificate to that effect on November 27, 1832. Ronquillo then sold the land, but without his troops subsequent owners found the area too difficult to settle. The last person to purchase the grant was Juana Pedrasa, who moved to Chihuahua, Mexico, and married Ben Leaton.
In 1887 Leaton's heir, Victor Ochoa, set out to claim the territory through investigation into the Ronquillo land grant. Leaton had already investigated Juana's claim in the 1850s but dropped the investigation when his attorney found a difficulty in the claim. The opinion was that Ronquillo's residence and improvement conditions could have been waived by the alcalde because of conflicting military duties, but the four-year holding period could not have been. In 1887 Ochoa hired Trevanion T. Teel, a San Antonio attorney, to confirm the grant for the Leaton heirs. Teel went to Juárez, Chihuahua, for research in the archives and discovered a decree he thought might prove the legality of the grant. He lost his copy before he could get it translated, however, and sent Ochoa to get another copy. Instead Ochoa substituted a forged document that confirmed the waiver of Alcalde Herrera. Teel, unaware of the switch, concluded that the grant was valid. In 1889 he filed two suits in the United States Circuit Court for the Western District of Texas on behalf of the Leaton heirs, claiming that they owned the land within the Ronquillo grant and that the state had violated agreements of the Treaty of Guadalupe Hidalgo and Article XII of the United States Constitution when they reassigned the land to the railways. One suit, against the mining companies for recognition of true ownership, requested $1 million in damages and $6,000 per month rental. The other, against the Texas and Pacific Railway Company, the Houston and Texas Central Railway Company, the St. Louis and Texas Railway Company, and the Galveston, Harrisburg and San Antonio Railway Company, asked for recognition of the grant by the court.
Meanwhile, an E. N. Ronquillo began investigations to claim the grant, asserting that the land had not been legally conveyed to the purchasers, and that it therefore could not belong to Juana Pedrasa Leaton, but remained the property of the heirs of José Ygnacio Ronquillo, who died in 1860 at San Elizario. E. N. Ronquillo sold his claim for a reported $100,000 to James J. Fitzgerrell of Las Vegas, New Mexico; with a partner, Fitzgerrell sold his rights to Ernest Dale Owen of Chicago and the Texas Land and Cattle Company for $4.5 million. Teel successfully challenged Ronquillo's claim by showing that his ancestor, José Ygnacio Ronquillo, was not the same Ronquillo as the one to whom the original grant had been issued. But the Leaton heirs fired Teel because he had failed to validate their claim to the land. In 1890 Teel dropped the suits he had filed in the circuit court.
Owen, however, continued to attempt to legitimize his claim. In early 1890 he filed seven trespass-to-try-title suits in the United States Circuit Court against the railroad, mining companies, and other claimants to title. He based his original argument upon the Juárez forgery, but when the railroad and mining companies alleged that it was a forgery, he examined it and agreed that it was invalid. He therefore sent researchers to Mexico to find the original document. When it was finally found in Santa Barbara, the decree did not have the governor's rubric. Owen bought the interests of all the contenders to title and 1892 brought his case to trial against the Presidio Mining Company. The court held that a valid grant was issued to José Ygnacio Ronquillo in 1832, but that Alcalde Herrera was unauthorized to waive the restrictions on the grant. In an appeal the United States Circuit Court of Appeals ruled in 1893 that the alcalde had no authority to make such a large grant after the Mexican colonization law of 1825. The court held that the Santa Barbara decree was a forgery and dismissed the case. After several other suits, Owen admitted defeat and concluded his eight-year, multimillion-dollar attempt to confirm the grant.