Final answer:
New Mexico shares its border with Texas to the west.
Step-by-step explanation:
The state that shares its border with Texas to the west is New Mexico. Regarding the other questions for context, during the war between the United States and Mexico, revolts against U.S. control broke out in New Mexico and California. In the geologic past, evidence suggests that the area including Texas, Oklahoma, New Mexico, and northeastern Mexico was part of a plate tectonic boundary. Lastly, as a result of the Adams-Onís Treaty, the United States gained the territory of Florida from Spain.