sentences:  San Juan Creek begins high in the Santa Ana Mountains southwest of Lake Elsinore, at the head of the steep and narrow San Juan Canyon, at roughly in elevation where Morrell Canyon Creek, draining the western Elsinore Mountains and southernmost Santa Ana Mountains, has its confluence with Bear Canyon Creek.From there, it flows steeply down a rocky gorge over rapids and waterfalls.San Juan Canyon forms the mountain pass for California State Route 74 (the Ortega Highway), which connects San Juan Capistrano to Lake Elsinore and the Inland Empire.