The Spanish province of Nuevo Santander, comprising the present Mexican state of Tamaulipas and part of trans-Nueces Texas, was founded by José de Escandón and named for his native province in Spain. Designated a province by viceregal order of September 3, 1746, the region was explored the following year by units converging from Texas, Coahuila, and Nuevo León, as well as those from Querétaro under Escandón's personal leadership. With actual settlement begun late in 1748, it was the last part of northeastern Mexico to be conquered and effectively occupied. Despite the lateness of its beginning, the Nuevo Santander population soon outpaced that of Texas, reaching 30,000 by the end of the century. The colony, initially called Colonia de la Costa del Seno Mexicano ("Gulf Coast colony"), grew from a series of proposals by Nuevo León governors and others for controlling the hostile Indians who took refuge in the coastal jungle and adjacent mountains. For more than two centuries the territory had been held by "indios bárbaros, pagans, and apostates." These natives, many of whom had suffered from Spanish slave raids and oppression in the haciendas, had resisted the inroads of Christianity and civilization, afflicting shipwreck castaways as well as settlers. Not only had they denied Spain the economic benefits of ports, salt deposits, and agricultural lands, but they had forced travelers between Mexico City and La Bahía, on the Guadalupe River in Texas, to take a route twice the shortest distance.
The original plan of conquest put forth by the Marqués de Altamira, auditor de guerra of the New Spain viceroyalty, called for colonizing both sides of the Rio Grande. The San Antonio River was to be the northern boundary. La Bahía Presidio and Nuestra Señora del Espíritu Santo de Zúñiga Mission were to be moved from the Guadalupe River to Santa Dorotea (the site of present-day Goliad) to serve as the colony's northern anchor. To link Nuevo Santander with the Province of Texas, two civilian settlements were planned: Villa de Balmaceda on the San Antonio and Villa de Vedoya near the mouth of the Nueces River. Before the coastal route could be proved, however, Vedoya's settlers despaired and went elsewhere. Neither Vedoya nor Balmaceda became a reality. Although the mission and presidio were moved in 1749 from the Guadalupe to Santa Dorotea, they remained in the Texas jurisdiction. The Nueces River, rather than the San Antonio, became Nuevo Santander's northern boundary.
From 1748 to 1755 two dozen settlements were made within the colony, most of them below the Rio Grande. Two were in the area of the present state of Texas: Laredo and an impermanent village of thirteen families called Nuestra Señora de los Dolores, farther down the Rio Grande. Other towns extended along the right bank of the river toward its mouth. Stockmen from these settlements gradually pushed their herds beyond the river, defying hostile Indians, water scarcity, and great distances to utilize the extensive grasslands. Yet this region received little official attention. José Tienda de Cuervo, visiting the colony as the head of an inspection commission in 1757, interrogated colonists to compile a description of each settlement but barely ventured beyond the Rio Grande. A decade later, the Ortiz Parrilla Gulf Coast expedition explored and mapped the Texas coast below the Nueces, revealing a dearth of knowledge of the entire littoral. At the time, Blas María de la Garza Falcón of Camargo maintained an estancia called Santa Petronila "five leagues" south of Corpus Christi Bay. Following the 1786 coastal reconnaissance by José Antonio de Evia, the Nuevo Santander governor proposed separation of the Texas portion of Nuevo Santander to form a new province. Manuel de Escandón, who had succeeded to his father's office and titles, envisioned new settlements at the mouths of the Rio Grande and the Nueces River, opening a river-borne trade to serve the interior. Because of the distance between the proposed new sites, Escandón thought it necessary to separate the area north of the Rio Grande from Nuevo Santander. He believed that such a move would enable a maritime commerce serving these and other northern provinces of New Spain, bring new settlers to the region, and form a link between Nuevo Santander and Texas. Thus, an alternative would be provided to the long overland trail from Mexico. Consideration of the matter, which might have been a step forward for both Nuevo Santander and Texas, was stalled by the death of Viceroy Bernardo de Gálvez. When Félix María Calleja inspected the province in 1795, he took note of the "almost nonexistent" commerce. He viewed the solution much as had Manuel de Escandón: the opening of ports on the Gulf. From Tampico to the Nueces River, he noted, the ports, bays, and river mouths were undeveloped and useless. Even so, the population had passed 30,000. A frontier ranching province, Nuevo Santander was both more populous and more opulent than the neighboring province of Texas. At this point it had one "city," 25 villas, 3 mining districts, 17 haciendas, 437 ranchos, and 8 missions.
Through a Nuevo Santander blacksmith named José Bernardo Gutiérrez de Lara and its governor Joaquín de Arredondo, the colony extended to Texas its involvement in events of the 1810 Mexican War of Independence: Gutiérrez in raising the Republican Army of the North; Arredondo in leading the victorious Royalist forces that defeated that army in the 1813 battle of Medina. From 1836 to 1845 that portion of the colony above the Rio Grande was the focus of a border dispute between Mexico and the Republic of Texas. Upon the annexation of Texas, the dispute erupted into war between the United States and Mexico. With resolution of the conflict, Mexican inhabitants of the "Nueces Strip" found themselves disenfranchised, living in occupied territory, and subject to a strange government and customs they did not readily understand. Yet these displaced persons and their descendants have given the region an enduring cultural legacy.