Cobre Ridge is a 14 mile loop trail located near Nogales, AZ and is rated as moderate. The trail is primarily used for mountain biking and is accessible year-round.
A outstanding bike loop down south of Arivaca and near the border. Spectacular scenery and even the ruins of an old smelter about 5 miles in. Ride counter-clockwise as there are numerous hills and dips. Some old wildcat mines along the road (two track the whole way) and active mines as well. You may encounter some hunters, but it seems even the Border Patrol doesn't go down here--never saw any all day. Took us 3 1/2 hours but we stopped a lot to take photos, look around, etc. Afterwards, stop at the La Gitana Cantina in Arivaca for beers and green chili cheese burgers. Great end to a wonderful day. Take plenty of water and bike repair stuff as you are miles from any help. Warsaw Gulch is a beauty and had flowing water when we rode this route.