Escandon's last forays into the area around Duval County

Another explorer sent into the area by Escandon was Tomas Sanchez, who asked the empresario for permission to found a settlement north of the Rio Grande. Escandon sent Sanchez to pursue Escandon’s dream of a settlement on the south banks of the Nueces. Sanchez, like Borrego, informed Escandon that the area was uninhabitable. Escandon gave Sanchez leave to settle on the north bank of the Rio Grande where he founded Laredo.
Escandon remained undeterred. In a 1764 report to his superiors, Escandon wrote that settlers in his towns: 
“have been extending themselves with ranches and haciendas, not only in the immediacy of said settlements but also in almost all the other shore of the Rio Grande del Norte and even further, nearly up to the Nueces River, about 20 leagues before the Presidio de la Bahia del Espirito Santo whose land is good for pastures and planting; notwithstanding that I understand the inspectors set it down as useless and sterile, an error that I attribute to their quickly believing someone who, without their having been in the region, gave them a report because they did not see it.”  
This again suggests that the San Diego area, which is well within 20 leagues (60 miles) before Goliad where La Bahia del Espirito Santo is located, may have already been under development. Escandon continued to press the crown for authority to settle the area beyond the Rio Grande, promising that it would not cost the Royal treasury.

In late 1767, the Rev. Padre Fray Jose de Solis embarked on a trip to visit the Spanish missions in Texas. He crossed the Rio Grande River, 30 miles south of Laredo. His journey took him first to Dolores and ultimately to La Bahia de Espirito Santo in Goliad. This trip, no doubt, took the priest through some parts of Duval County, as the county is directly between the area on the Rio Grande the priest crossed over into Texas and Goliad. 

Father Solis reported that the Apache Indians inhabited the area between the Nueces and Rio Grande Rivers. He said he passed through some rolling hills and large plains and saw woods that included “mesquites, palms, prickly-pears, chaparrals, oaks and other kinds of trees.” In the woods, he found bears, wildcats, snakes, and other animals.   

In 1828, the Mexican government sent a 38-year-old general, Manuel de Mier y Teran, to assess the natural resources of Texas. Teran was also to prepare a report on the history of Texas settlements and gather geographical data for the Border Commission. On his return from the Texas-Louisiana border, Teran traveled through the South Texas region. 

While he likely did not come through what is now Duval County, he spent some time in the Agua Dulce, San Fernando and Santa Getrudis area. These are in Nueces, Jim Wells and Kleberg Counties, respectively. His observations of that region would certainly be akin to the Duval County area. 

Teran wrote in his diary that the land was “a continuous plain.” The flatlands caused rainwater to collect in lowest spots. Teran reported that it was necessary to post guards to watch the horses and mules, to keep them from running off with numerous mesteños, the wild and unbranded cattle found in the area.