Round Top Mountain is located in the Trans-Pecos region of West Texas, northeast from the Mexican border. The region is the most mountainous area of Texas, and lies to the southeast of the Sierra Blanca mountain range. The area includes the Finlay Mountains, Triple Hill, and Sierra Blanca quadrangles as well as parts of the Fort Quitman and McNary quadrangles. The Sierra Blanca area is approximately . Round Top Mountain is one of five peaks made from laccoliths in the area, with the others being Little Round Top, Little Blanca, Triple Hill, and Sierra Blanca. The area lies between the northern Quitman Mountains and Devils Ridge.