The Boulder River is a tributary of the Yellowstone River that originates high in the Absaroka Mountains south of Big Timber, MT. Natural Bridge Falls is the main attraction on the Boulder but the river and surrounding lands provide incredible opportunities for fishing, camping, and exploring.
The Boulder River Valley
The headwaters of the Boulder River are in the Absaroka Beartooth Wilderness. This vast wilderness borders Yellowstone National Park and is one of the wildest areas in the lower 48 states. The Boulder begins from snowmelt in the high mountains. It travels nearly 30 miles through US Forest Service land before leaving the mountains. The river canyon opens into a broad open agricultural valley. The Boulder River has long been renowned within Montana for its excellent recreation opportunities. Many residents will tell you that the Boulder is one of their favorite places to visit.
State Hwy 298 parallels the river until the National Forest boundary where it becomes the Boulder River Road. Heading South from Big Timber, MT, Hwy 298 is an excellent paved road that runs through a broad valley studded with family ranches. This is productive agricultural land and the working ranches that fill the valley remind us of the traditional Montana lifestyle. The lands surrounding the river are private property and it’s difficult to access the river through this stretch.
About 16 miles south of Big Timber is the tiny town of McLeod, MT. The first post office in the Boulder valley opened here in 1886. Don’t expect to find much here today. The town is at the junction of the West Boulder and main Boulder Rivers. The West Boulder River is a sizable tributary that is well known for its fly fishing and great hiking trails. A gravel road intersects with Hwy 298 near McLeod. This road is called the East Boulder Road but becomes the Swingly Road after a bit. The Swingly Road travels cross country to the outskirts of Livingston. It makes a great drive as well as providing access to hiking trails and other explorations.
Past McLeod, Hwy 298 continues south toward the rapidly approaching mountains. It’s about three miles to the East Boulder River where an access road leads to several trailheads in the East Boulder Drainage. The East Boulder is a significant mining area that was first developed in 1893 when Ansel S. Hubble, one of the first prospectors in the area, filed claims in the drainage. Today, the East Boulder Mine is a major underground mine that producing large amounts of platinum and palladium.
Natural Bridge Falls
5 miles south of the East Boulder junction the paved road ends and you enter the Gallatin National Forest. Almost immediately the Natural Bridge Falls Picnic Area is on the left. This Forest Service day-use area is a fantastic place to visit and well worth the trip to see.
At the Natural Bridge Falls, the Boulder River pours over the lip of a 105-foot tall limestone rock layer. This rock is soft and easily eroded and historically there was a beautiful natural bridge that spanned the river here. Unfortunately, the Natural Bridge collapsed in 1988 and all that remains are memories and photos. However, the falls remain and they are spectacular.
The limestone rock layer erodes easily and several major underground channels have been cut through the rock. In low water the entire river goes underground above the falls. The river erupts from several places to come bursting out of a cliff wall. At high water these streams are joined by the bulk of the river pouring over the lip.
The Natural Bridge Falls parking area is right next to the road where the highway ends and the gravel road begins. There are handicap-accessible vault toilets, paved trails, interpretive signs, and numerous river overlooks. This is also the trailhead for the Green Mountain Trail which is reached by crossing the river on the sturdy bridge. Casual visitors will want to cross the river and follow the trail heading downstream. It is a short walk to the vantage points opposite the Falls where the photos on this page were taken. The hike is about a 1/4 mile on a gentle trail through a mixture of clearings and forested areas.
Kayaking Natural Bridge Falls
Natural Bridge is an impressive falls. At high water the Boulder is a significant river and the water shoots over the falls with an amazing force. The Boulder River has always been the playground for boaters (mostly kayakers) and it’s easy to imagine that many have looked at the falls and wondered if it would be possible to survive an attempt at jumping the falls.
One man decided that he had to find out and in 2008 Bozeman native Ian Garcia kayaked over the falls. Ian is a noted waterfall jumper and had studied this for years. Ian survived the jump but did have a swim after being ejected from his boat. Read more about kayaker boats over Natural Bridge Falls.
Although most boaters avoid the Falls, the upper Boulder is popular with whitewater kayakers who come to enjoy its wild waters. The 20 plus miles of river above Natural Bridge offer some very difficult waters and serious boaters flock to the Boulder for spring runoff. If you want to float these stretches of the river you must be prepared. This website is not the place to get the info you need. Do your homework and don’t consider boating on the Boulder until you are certain you are prepared for the boating conditions.
The Upper Boulder River
From Natural Bridge the road continues for about 25 miles, making a very deep incursion into the heart of the Absaroka Beartooth Wilderness. This road can be very rutted and slow driving so don’t ever plan to hurry. There are a number of private in-holdings along the road but most of the land is National Forest. There are about a half dozen USFS developed campgrounds along the road. These all have toilets and some have water. Most charge a small nightly fee. In addition, there are many dispersed camping spots on forest land along the road and river.
Besides the camping opportunities, the USFS operates the Fourmile Cabin as a rental cabin. The cabin is about 15 miles south of Natural Bridge Falls. It sleeps 4 and is available for a modest fee on a reservation basis.
Into the Absaroka Beartooth Wilderness
Beyond the end of the Boulder River Road there are jeep trails that lead even higher and further. There was a history of mining on the highest mountains in the area and there are private mining lands at the top of Independence Peak, which is to the east of the River. I don’t recommend that you try to travel these 4wd roads. Rather, stay with the main road which ends at about 8,000 ft elevation in a meadow surrounded by 10,000 ft peaks. From here there are trails into the Absaroka Beartooth Wilderness. This is beautiful mountain country.
The Upper Boulder is classic mountain terrain and there are great hiking trails that take off from trailheads along the road. The upper sections of the Boulder River are just over the mountains from the Paradise Valley of the upper Yellowstone River. Head west from the upper Boulder and you will encounter Crow Mountain which is reached from the Mill Creek drainage on the other side of the mountains.
If you want to visit these areas make sure you have appropriate maps. USGS topo maps are available from local hiking stores. The Absaroka-Beartooth Wilderness West National Geographic Trails Illustrated Map fully covers the area and the DeLorme Montana Atlas & Gazetteer has topo maps of the entire state.
Fishing The Boulder River
The Boulder River is a famous fishery and fly fishermen from afar visit to fish for the wild trout that inhabit its waters. The Boulder River is a very popular fishery for native Yellowstone cutthroat trout and mountain whitefish as well as for wild brown and rainbow trout. The river is open to fishing all year long but most anglers find the best success in summer and fall. There is a reason that people come from around the world to fish here!
The upper river has almost unlimited access as the road runs very close to the river for many miles. Since this is almost all Forest Service land you can fish wherever you think it looks likely. However, below the forest boundary access is a lot tougher. Just outside of McLeod there is a Montana State Fishing Access Site located on the river. The Boulder Forks Fishing Access Site offers great access to an excellent fishing section of the Boulder River.
The Boulder River drainage makes a great place to escape into the mountains of Montana. It offers great hiking, camping, fishing, and, for the very experienced, great whitewater boating. This is a wonderful place to go for a quick escape or for an extended expedition. Natural Bridge Falls is a very spectacular natural feature that anyone interested in Montana should see. Be sure to take the opportunity to visit this great area.
Frequently Asked Questons
Natural Bridge Falls is 25 miles south of Big Timber on US298 (the Boulder River Road). The road is paved until just before the falls.
Natural Bridge Fall is about 105 ft when the water is flowing over the top lip of the falls.
Natural Bridge Falls was once spanned by a large bridge over the river. The bridge collapsed in 1988.
There is no camping allowed at the Natural Bridge site. However, there are nearby campsites along the Boulder River Road.
The Natural Bridge site is open 24 hours a day year-round. It is not a staffed site so you can visit any time.
It is free to visit the falls.
All Montana fishing rules and regulations apply on the Boulder River, including the standard statewide fishing license requirements.
Cutthroat trout and mountain whitefish are native to the Boulder River. Today there are also wild rainbow and brown trout.
The Boulder River was stocked in the past but today there is no fish stocking of any sort. All of the fish in the river are wild.
The West Boulder River is a major tributary that enters the Boulder River about 8 miles downstream of Natural Bridge Falls. The rivers intersect in McLeod, MT.
Nearby attractions in the Big Timber area: