One from a series of maps from A.B. Gray and the Joint Boundary Commission, this is the product of a three-year survey conducted along Texas’ eastern border. Although the 1819 Adams-Onís Treaty had established the boundary between Spanish Texas and the United States, no commission had been established to map it. It was not until the establishment of the Joint Boundary Commission that the eastern border of Texas was finally set. As mentioned in the title, this sheet focuses on the boundary north of the Sabine River from the 72nd mile mound to the Red River.