In the 1790s, Spanish Tejas contained less than 4,000 people (as the Spanish understood the term, so not including 'wild' Indians) - including 1,000 garrisoned troops, and all the converted Indians, whose loyalties were flexible at the best of times (Some Apaches once 'converted' just to get the Presidio San Luis de las Amarillas built in Comanche territory, to see what happened. You can imagine what happened). Although a bit earlier than the period of your interest, the reports of the Marqués de Rubí are a good period source. He rolled up in Spanish Tejas as part of a general inspection set up due to the waning French threat in the area. What he saw was a scattered bunch of wretched settlements under constant Apache and Comanche threat, and which couldn't hold the land nor even protect themselves. Spanish Tejas was not real, it didn't exist. He advised Tejas be entirely abandoned, except for Presidio La Bahía and San Antonio de Béxar, with the removal of all East Tejans to San Antonio, with the establishment of a line of forts which pretty closely mirrors the modern US/Mexico border. "The country," he said, "should be given back to Nature and the Indians." In 1772, by royal order, it was. The only other settlement was Nacogdoches, which was resettled by its Spanish inhabitants against orders, and which was in 1779 declared the first town in Tejas.
By the 1790s, the Spanish still didn't understand you can't make treaties with Indians. For one thing, there was no real cohesive government body. Dudes hung out with powerful leaders; if the leaders did something they didn't like, such as make a treaty, they'd just wander off. And then kill more Spaniards. 1792 was a particularly bad year, and in 1793, with the outbreak of what we call the Napoleonic Wars, Spain lost almost all interest in Tejas and its 4,000 people. Around 1800, you're looking at the only towns of note being San Antonio, Presidio La Bahía (Goliad), and Nacogdoches, having about 2,000, 1,500, and 500 souls respectively.
Persons of interest:
Philip Nolan was an Irishman who mapped much of Texas and engaged in a shitload of illegal horse trading in the 1790s. He saw what Rubí did - weakness. He teamed up with the hilariously duplicitous American General James Wilkinson, who thought it would be a good idea to break off Tejas from Spain. This was in between his plans to break off Louisiana from France and the Old Southwest from America. In 1800, Nolan and some 20 dudes entered Tejas well-armed, either to gather some new horses or to launch an invasion, depending on who you ask. The Spanish were jumpy about him and claimed he had a plan to crown himself as el Rey de Tejas, and he was shot and killed in a skirmish with Spanish soldiers. Wilkinson turned his plans to split off Tejas, or Mexico, or Louisiana, or Tejas and Mexico and Louisiana, towards another sympathetic ear, that of Vice-President Aaron Burr, who (then out of office) in 1805 went southwest to raise support, arms, and men. Ultimately Wilkinson, aka Agent 13 of the Spanish Crown, dropped the dime on Burr. The running assumption is he suckered Burr in with the idea to go after Mexico and/or Tejas, then told others it was a plan to go after Louisiana, to paint Burr a traitor, for whatever reason. Weird times, interesting guys.
