Oriflamme Canyon is a steep canyon in the Laguna Mountains of San Diego County, descending to Rodriguez Canyon at the northwest end of Mason Valley, where Vallecito Wash begins. Long before modern development, it formed part of an older travel route linking mountain and coastal areas of present-day San Diego County with the peoples of the Colorado River region. The same passage was later used by Spanish, Mexican, and American travelers. It also served U.S. Army couriers and the San Antonio–San Diego Mail Line, whose passengers rode mules through the canyon between Carrizo Creek Station and Lassitor's Ranch in Green Valley on a shorter route toward San Diego.