The Old Spanish Trail is an historical trade route that connected the northern New Mexico settlements of (or near) Santa Fe, New Mexico with those of Los Angeles, California and southern California. Approximately 700 mi (1,100 km) long, the trail ran through areas of high mountains, arid deserts, and deep canyons. It is considered one of the most arduous of all trade routes ever established in the United States. Explored, in part, by Spanish explorers as early as the late 16th century, the trail saw extensive use by pack trains from about 1830 until the mid-1850s.