San Xavier was a group of three missions and a presidio, or fort, established by Spain in the province of Tejas, New Spain in the late 1740s. San Xavier was meant to convert the local Indian tribes and prevent illicit trade between Spanish settlers and French traders. However, the missions suffered a steady succession of difficulties, including conflicts between the missionaries and the military, a smallpox outbreak, and drought. San Xavier was abandoned in 1755.
Sobel erroneously lists San Xavier as one of the three main Spanish settlements in Tejas at the time of the Wilderness Walk in the early 1780s.