River Road crosses the remote southern edge of Big Bend National Park, roughly linking Rio Grande Village in the east with Castolon in the west. The Park Service describes it as traversing the remote southern portion of the park. Despite the name you will rarely see the Rio Grande: the road runs well back from the river, and the water is reached only by side roads to the riverside campsites.
People drive it for the distance and the quiet, for the ruins of the Mariscal quicksilver mine at its midpoint, and for campsites with no neighbours. What follows is the agency’s own account of the road: its length, the time it takes, the vehicle it requires and the rules for camping along it. NPS posts condition notices at the top of its River Road page. Read the current one before you commit.
What the River Road is
NPS gives the length as 51 miles and describes a road that travels through and across many desert washes. It generally follows the course of the Rio Grande but runs a considerable distance from it, especially in its mid-section near Mariscal Mountain. In the agency’s words, you cannot actually see the river along the River Road unless you take a side trip to one of the primitive roadside campsites beside it.
Because of its length and usually rough condition, NPS says to allow a full day to drive it from end to end. The highlights it names are the Mariscal Mine and access to the Mariscal Rim Trail, a 6.5 mile round trip hike it describes as rugged but spectacular.
NPS also offers advice worth taking seriously. The west side of the road is less used and generally rougher. Unless you have full confidence in your high clearance vehicle, it suggests backtracking from the Mariscal Mine and returning by Glenn Springs Road rather than completing the traverse.
Source 1
The road from east to west
NPS lists the campsites east to west, and its campsite pages give the mileages that let you follow the road in order. They measure the east side from the main paved road to Rio Grande Village and the west side from the end near Castolon. The figures do not always agree to the mile with the 51 on the River Road page, so treat them as approximate and keep the park map open.
Every one of these pages repeats the same warning: after rain the road is extremely muddy and may quickly become impassable to all vehicles.
NPS campsite list, east to west, with the mileage each page gives
- 01Gravel Pit (3 sites): access road 1.8 miles from the paved road, then 1.4 miles to the sites and the river.
- 02La Clocha (2 sites): 2.6 miles from the paved road, on a 0.7 mile access road NPS calls very rough.
- 03Solis (2 sites): 13.7 miles in, on a 1.7 mile river access road.
- 04Fresno (1 site): 18.6 miles in, with views of the Mariscal Mine ruins.
- 05Elephant Tusk (1 site): 3 miles up Black Gap Road, which NPS places 21 miles from the east end of River Road.
- 06Talley (4 sites): the Talley Road junction is 23.2 miles in. The side road runs 6 miles to the river, and NPS says its last mile may require four-wheel drive.
- 07Dominguez Trailhead (1 site): 22.7 miles from the west end.
- 08Loop Camp (2 sites): junction 23 miles from the west end, then a 3.5 mile access road to a bluff above the river.
- 09Johnson Ranch (2 sites): 15.6 miles from the west end, near the ruins of a ranch and trading post. Camping is prohibited near the ruins.
- 10Gauging Station (1 site): 14.2 miles from the west end.
- 11Black Dike (1 site): 10.7 miles from the west end.
- 12Buenos Aires (2 sites): 4.4 miles from the west end, the closest River Road campsite to Castolon.
Source 2
Mariscal Mine, the midpoint
Mariscal Mine, a National Register Historic District on the northern end of Mariscal Mountain, is the natural turnaround for anyone who takes that advice and drives only the east half. NPS says that between 1900 and 1943 the mine produced 1,400 flasks of mercury, nearly one quarter of United States production, and that it closed for the last time a year before the park was established.
The agency says the easiest access is by River Road East, which begins five miles west of Rio Grande Village, and that you should allow at least half a day for the excursion.
Treat the site with care for your own sake. NPS asks visitors to stay off the structures, which are old, fragile and unsafe, and to avoid handling the bricks of the Scott Furnace or the mine tailings, which may contain poisonous concentrations of mercury. Most of the vertical shafts are fenced, but it warns that unfenced ones may exist. Collecting anything is prohibited.
Source 5
Vehicle and driver requirements
The River Road page is blunt: travel on this primitive road requires high clearance and true four-wheel drive, and it is not passable to passenger cars, minivans, motorhomes or small crossover SUVs. NPS defines a high clearance four-wheel-drive vehicle as an SUV or truck with rims of at least 15 inches, a low gear transfer case, at least 8 inches of clearance from the lowest point of the frame, body, suspension or differential, and a means of mechanically powering the front and rear wheels together. Off-highway vehicles and ATVs are not allowed.
Its backcountry road safety page adds the driving advice. Go slowly. If you meet an obstacle beyond your vehicle’s limits, turn around. Keep track of how far you have come in case you have to walk back. If the vehicle is disabled, it is almost always best to stay with it. If you must walk, carry water, stay on the road and leave a note on the dashboard.
What NPS tells backcountry drivers to carry
- 01A good spare tire, a tire repair kit and pump, and the tools to change a tire
- 02Extra belts and hoses, and extra coolant or water for the radiator
- 03A shovel, in case the vehicle bogs down in sand
- 04Plenty of water, and high energy food that keeps
- 05A first aid kit, and sleeping gear for an unplanned night
- 06A map of the park
Do not skipNPS: “A disabled vehicle on Big Bend’s isolated roads can be a life-threatening situation.” Check conditions at a visitor center and tell someone your route and return time before you start.
Source 6
Camping along it and the permit
You may camp only in the designated primitive roadside campsites, and only with a backcountry use permit. NPS allows no dispersed camping anywhere in the park. The River Road sites are among the 47 that are issued only in person at Panther Junction Visitor Center, open daily from 8:30 am to 5:00 pm, up to 24 hours before your first night: the day of, or the day before. NPS says rangers will not issue these permits for a passenger car, minivan or RV.
Each site is a small flat gravel space beside your vehicle, with no shade, toilets or other amenities, and generators are prohibited. Each campsite page sets its own vehicle and people limits, and several bar trailers. NPS says these sites are typically occupied most nights of the year, so have second choices ready.
As of September 2026 the NPS Backcountry Use Permits page puts the cost at $10 per night, or $5 with a Senior or Access pass. The park entrance fee is separate.
Source 7
Fuel, water and distances between services
There is no fuel, water or any other service on River Road. NPS lists two service stations in the park: Rio Grande Village, near the east end, with gas, diesel and propane, and Panther Junction, with gas and diesel. At the west end it lists a convenience store at Castolon and no service station. Outside the park it lists gas and diesel at Study Butte and gas at Lajitas. Confirm hours before you count on any of them.
Work out your range before you start: 51 miles of slow driving, side roads to the river that add miles of their own, and the paved miles back to a pump. NPS gives the whole Ross Maxwell Scenic Drive, the paved road that serves Castolon, as 30 miles, and the road between Panther Junction and Rio Grande Village as 21 miles.
NPS recommends one gallon of water per person per day, and tells backcountry drivers to carry plenty more, because you may meet someone out there who needs it.
Source 9
Heat, rain and the border
River Road runs through the low desert near the river, the part of the park NPS says is hotter than the forecast. It says the desert floor is usually well above 100 degrees Fahrenheit by late morning from May through August, and that the desert and river corridor run about 10 degrees hotter than the Panther Junction forecast. The rainy season is July through September, with locally heavy thunderstorms and some flash flooding possible. The River Road page says the road crosses numerous washes and regularly becomes impassable after rains.
The campsite pages carry border cautions of their own. It is illegal to cross the river and enter Mexico. NPS asks campers to secure belongings when away from camp and while sleeping, and warns that theft has been a problem at the Solis sites. It describes Elephant Tusk as a very remote site with very little vehicle traffic. Plan the whole road as if nobody will come by.
Source 11
Leaving it as you found it
Motor vehicles are permitted only on designated public roads, and NPS prohibits off-road driving throughout the park. Ground fires and wood fires are also prohibited. At roadside campsites you may burn only pressed charcoal briquets in a grill, and you pack out the cold ash.
Camp inside the designated site, with tents on bare ground within the area marked by rocks, logs or brush. Store all food, water, trash and anything scented in a hard-sided vehicle, or in a bear resistant locker where one is provided. Bury human waste at least 6 inches deep and pack out the toilet paper, along with every other scrap of trash. Pets may go only where vehicles can. Collecting or disturbing any natural or historical object is prohibited, and NPS counts old cans and bottles as part of the archeological record.
Source 12
Questions people ask
How long is River Road and how long does it take?
NPS gives the length as 51 miles and says to allow a full day to drive it from end to end, which its campsite page puts at 5 to 7 hours. Side trips to the river and to Mariscal Mine add to that.
Do I need four-wheel drive for River Road?
Yes. NPS says travel on the road requires high clearance and true four-wheel drive, and that it is not passable to passenger cars, minivans, motorhomes or small crossover SUVs. Its definition calls for rims of at least 15 inches, a low gear transfer case and at least 8 inches of clearance.
Can I camp anywhere along River Road?
No. You may camp only in the designated primitive roadside campsites, with a backcountry use permit issued in person at Panther Junction Visitor Center up to 24 hours before your first night. There is no dispersed camping in Big Bend.
Can I take a trailer or an RV?
NPS says you will not be able to reach these campsites with a passenger car, minivan, RV or trailer, and that rangers will not issue permits for those vehicles. Several campsite pages bar trailers outright.
Is there fuel or water on River Road?
Neither. NPS lists service stations at Rio Grande Village, near the east end, and at Panther Junction. The campsites have no water or any other amenity, so carry everything you will drink.
Can you see the Rio Grande from the road?
Rarely. NPS says the road runs a considerable distance from the river and that you cannot see it unless you take a side trip to one of the riverside campsites.
Bureau of Land Management (BLM)
US Forest Service (USFS)
National Park Service (NPS)
US Fish and Wildlife (USFW)
Bureau of Reclamation (USBR)
Department Of Defense (DOD)
Bureau of Indian Affairs (BIA)
Other Federal
State
Local
Alaska Native Lands (Patented or Interim Conveyed)
Alaska Native Allotment
Road
Primitive Road
Road
Primitive Road
Trail
Roads open to all Vehicles, Yearlong
Roads open to all Vehicles, Seasonal
Roads open to highway legal vehicles only, Yearlong
Roads open to highway legal vehicles only, Seasonal
Special Designation, Yearlong
Special Designation, Seasonal
Trails open to all vehicles, Yearlong
Trails open to all vehicles, Seasonal
Trails open to vehicles 50" or less in width, Yearlong
Trails open to vehicles 50" or less in width, Seasonal
Trails open to motorcycles, Yearlong
Trails open to motorcycles, Seasonal
Special Designation, Seasonal
Trails Open to Wheeled Vehicles Only < 50" in Width, Yearlong
Trails Open to Wheeled Vehicles Only < 50" or Less in Width, Seasonal
Wilderness Area
Wilderness Study Area