Sierra San Pedro Mártir, mountain range in central Baja California state, northwestern Mexico. The range stretches southward about 90 miles (145 km) from southeast of Ensenada to San Fernando. Farther south the range becomes the Sierra de San Borja. The rugged, granitic mountains, forming the divide between the Gulf of California and the Pacific Ocean, rise to an elevation of 10,069 feet (3,069 metres) above sea level at the peak of La Encantada. Although the surface is largely barren, some valley bottoms have fertile soil, and the mountains are rich in minerals (copper, silver, gold, and lead). Settlement in the area is sparse, but paved roads connect most of the towns.