Brazos Mountains to 55 million years ago during the Laramide orogeny. To the east and northeast lie the Sangre de Cristo Mountains which share a similar geological history. The Brazos Cliffs, which form a dramatic backdrop to Tierra Amarilla, are formed of Precambrian quartzite. Brazos Mountains The Brazos Mountains is a range in far northern Rio Arriba County, in northern New Mexico in the southwestern United States. A high crest runs from the border with Colorado for over in a south-southeasterly direction. The high point of the range at is on Grouse Mesa, at the Brazos Benchmark. Two miles (3 km) to
Washington-on-the-Brazos, Texas virtually abandoned. The State of Texas purchased of the old townsite in 1916 and built a replica of the building where the delegates met. The state acquired more of the site in 1976 and 1996. Located between Brenham and Navasota off State Highway 105, the site is now known as Washington-on-the-Brazos State Historic Site. It covers , and features three main attractions: Independence Hall, Barrington Living History Farm, and the Star of the Republic Museum, which is administered by Blinn College. The site's visitor center is free and includes interactive exhibits about the Texas Revolution and the park's attractions, a