Prior to its use as ranch land, the Diablo Range backcountry now covered by Henry W. Coe State Park was traversed by La Vereda del Monte, a trail between Point of Timber on the Sacramento River Delta and Cantua Creek in the San Joaquin Valley. Joaquin Murrieta and his gang used the route to drive wild or stolen horses south from Contra Costa County, picking up more from stations along the way, passing into the area of the park from the San Antonio Valley via a trail that closely followed the route of County Line Road along the divide of the Diablo Range. Horses were held at several locations now contained within the park, including Valle Atravesado (now flooded by Mississippi Lake), Valle Hondo, site of Pacheco Camp, Paradise Flat and Mustang Flat. Both Mustang Peak and Mustang Flat derive their names from the activities of Murrieta and his gang. Mustang Peak is where the horses held at Paradise Flat or Mustang Flat were fed into a passing drove.: