LaSal Mountains, laccolithic segment of the Colorado Plateau, extending across San Juan and Grand counties in eastern Utah, U.S. Of volcanic origin, the peaks rise to Mount Peale (12,721 feet [3,877 metres]), the highest point in the Colorado Plateau. The region is largely embraced by a division of the Manti-LaSal National Forest. The main economic activities are mining and lumbering. The Domínguez-Escalante expedition (see Silvestre Vélez de Escalante) explored the region in 1776 and named the mountains the Sierra de la Sal for their abundant salt (Spanish sal) deposits.