Los Adaes was for more than half a century the easternmost establishment in Spanish Texas. Its primary purpose was to block French encroachment upon Spain's southwestern possessions. Including both San Miguel de Linares de los Adaes Mission and Nuestra Señora del Pilar Presidio, the settlement conformed to the Spanish practice of utilizing these frontier institutions in combination both to serve and to control local Indians. The mission at Los Adaes was founded by Domingo Ramón by 1717 but was abandoned in 1719 when threatened by the French. The reestablishment of the Spanish presence, near the location of present-day Robeline, Louisiana, occurred under the direction of the Marqués de Aguayo. His expedition established the presidio and reoccupied the mission at Los Adaes in 1721. Upon completing his task Aguayo left the continued enactment of Spanish frontier policy to a few Franciscans and 100 cavalry troops. Eight years later, in 1729, two decisions by Spanish authorities further defined the character of Los Adaes. The Viceroy's Regulation of that year designated Los Adaes as the capital of Texas. In addition, the garrison was reduced to sixty to lessen the expense of defending the Spanish frontier in North America.
The reduction in the number of troops stationed at Los Adaes was encouraged by the absence of a local Indian threat. The Caddoan-speaking groups of the surrounding region, including the nearby Adaes Indians, were friendly. Indeed, these groups were inveterate enemies of the troublesome Lipan Apaches, who posed a constant threat to Spanish settlement farther west in Texas. The friendly Indians insulated Los Adaes from hostile Indians. Despite cordial relations with the local natives, however, the Franciscans at Los Adaes were unsuccessful in their attempt to resettle them at the mission. The ability of these Indians in their scattered hamlets to provide themselves with a constant food supply militated against the missionaries' efforts. In 1768 the College of Nuestra Señora de Guadalupe de Zacatecas, which directed the missionary activities at Los Adaes, admitted to the failure of its exertions among the Indians when it officially abandoned its labors in this region.
The location of Los Adaes, far from the centers of governance and supply in New Spain, did much to mold the character of the settlement. In effect Los Adaes and the other Spanish settlements in East Texas composed a pocket of isolated Spanish settlement connected with New Spain only by a slender thread of overland communication. The major trail west, a Camino Real, was nothing more than a path. Swollen streams and hostile Indians frequently interfered with travel over this route. The isolation of the Adaesans turned them of necessity to the French at nearby Natchitoches, on the Red River in Louisiana, for assistance. Food supplies such as corn, beans, and wheat were supplied to the Spanish in significant quantities from this source. That the Spanish recognized the need for this trade is confirmed by the fact that they constantly relaxed restrictions on commerce in foodstuffs. Though trade in other goods was prohibited, illicit commerce developed across the frontier in spite of the exertions of Spanish authorities. French trade items, which made up part of this commerce, were important elements in the Indian trade carried on by the inhabitants of Los Adaes. It is ironic that Los Adaes, which was established to protect East Texas from French encroachment, found itself dependent upon the French settlement that it confronted.
Aside from the military character of the garrison and the religious nature of the mission, a wide diversity of occupations existed at Los Adaes among the civilian populace. Included among these were cattle tending, woodcutting, blacksmithing, and domestic service. Many settlers were also involved in the deerskin trade with the Indians as well. The worst time for the Adaesans came in the mid-1730s. Crop failures, severe weather, and inadequate supplies from New Spain combined to produce a desperate state of affairs. Although the settlers did not experience such severe circumstances again, life at Los Adaes nevertheless continued to remain harsh. The character of the East Texas borderlands was altered with the transfer of French Louisiana to Spain in 1762. Los Adaes no longer confronted French Louisiana. Instead, East Texas now bordered on Spanish Louisiana. Prompted by these new circumstances, the Spanish government undertook a reorganization of the North American frontier following the design of the Marqués de Rubí. Acting on Rubí's recommendation, the Spanish crown issued the Royal Regulation of 1772, a decree by which Los Adaes was ordered abandoned and the capital of the province was transferred to San Antonio de Béxar. The inhabitants of Los Adaes were ordered removed to the San Antonio area. After painfully short notice in June 1773, a population estimated to number nearly 500 found itself uprooted. Despite official instructions, however, the Adaesans did not resettle at San Antonio. Instead, exhibiting an independent spirit nurtured by their experience on an isolated frontier, they returned to East Texas, where, after their disappointing stay in Bucareli, they established the permanent foundations for Nacogdoches. For some fifty years the settlement at Los Adaes, including both the presidio and mission, had endured and had maintained the Spanish presence in the borderland region of East Texas. But just as in 1721, when its foundation was the product of government policy, so in 1773 government policy was responsible for the end of the garrison and the mission.