Trails accessible from Bridger Canyon Road. East on Main Street and left on Rouse. Drive N on Rouse out of town where it curves right to become Bridger Canyon Rd.
The M trailhead is closest and most popular (driving 10 min, 6 mi). Trailhead is left just past Fish Hatchery. Two trails start here, Foothills and Baldy. Baldy trail (4300 of gain in 5 miles) is either straight up to the M or easier switchbacks to the M. This is an ideal workout for serious trail running. It is close, steep, lots of elevation, and all single track. Continue above the M on the only prominent trail. This entire trail is quite steep with two short level portions to catch your breath. You can make a loop by coming back down from Baldy summit about 1/3 mi watching for a nice trail to the right (Sypes trail). Go down Sypes about 2 miles to a distinct junction at the beginning of a long level spot.. Go left on the Foothills Trail and back to the M (more info on Sypes and Foothills below). From Baldy Peak you can also continue north along the ridge another 7 miles past Bridger Bowl Ski area to intersect the Foothills Trail at Ross Pass. This trail disappears in rocks from time and time and occasionally has horrible footing. It is the course for the Bridger Ridge Run in August. Baldy is a year around trail, though snowshoes are generally needed Dec - March. After that the snow is usually packed or melted.
The Foothills trail (11,000 in 22 mi one-way) was designed by a demon to obtain the maximum elevation gain possible. Probably one of the less rocky trails but mostly steep up or steep down. It begins at the M and almost all of the Bridger trials intersect it causing for a myriad of combinations and loops as it traverses the western slope of the Bridgers, crossing over to the eastern slope just past Sacajawea Peak (9,400) to descend to Fairy Lake. Every intersection is either well-marked or is straight ahead so navigation is not a problem. 3 mi to Sypes, 6 mi to Middle Cottonwood, 13 mi to Truman, 16 mi to Ross Pass. Once past the stock tank 2 miles past Truman Gulch there is no more water (after snow is melted in late June).
Run up from Bridger Bowl Ski Area (driving 25 min, 16 mi) to access the ridge (2500 in 1.5 mi). Park at the main lodge or drive up the road going right around the lodge another mile to park at the gate. The trail goes up near the highest ski lift, very, very steep. At the ridge you can go in either direction (south 3 mi to Saddle Peak, 5.5 mi to Baldy, north 3 mi to Ross Pass) but the trail is both rough and occasionally illegible in this area. Great place to watch raptors migrating in late Sept and Oct.
Drive on to Brackett Creek (driving 25 min, 18 mi) to go up into the Bangtails (subsidiary range east of the Bridgers). 2 miles N of Bridger Bowl at the bottom of a hill is Brackett Creek. Parking on the right. Grassy Mountain trail to Olson Creek. The trail goes out of the east end of the parking lot. I havent been on this but I hear it is a nice 23 mile (one-way) trail. You can also run, walk or drive west into the Bridgers on 4-wheel drive roads nearly to where the Foothills Trail goes through Ross Pass in the Bridgers (2000 in 3 mi). It is almost a technical climb up scree chutes to bag Ross Peak (9,100).
Fairy Lake trailhead allows you to bag the two highest peaks in the Bridgers in 6 miles (driving 50 min, 26 miles). 19 miles up Bridger Canyon Rd, left just past Battle Ridge summit, then 7 miles more on decent gravel road. Rustic campground near the trailhead. Trailhead is at the parking area above the campground. Up rocky cirque to a saddle (900 in 1.5 miles). Trail forks several times but always rejoins itself. Lots of switchbacks on a solidly rocky, shale trail. At the saddle go right less than a mile (500) to Hardscrabble (9,300), quite difficult but not technical. Left 1.5 miles (600) to Sacajawea (9,400), good trail. Be careful to initially stay left on the ridge and not go down the Foothills Trail back to the M.
Trails accessible from Springhill Road. West on Main Street then left on N. 7th. North on N 7th across I-90 where it curves left a mile to the Exxon station. Right (north) on Springhill Rd. Also can take N. 19th or exit 305 from I-90 to the Exxon station.
Sypes Canyon Trail (driving15 min, 11 mi). 1.5 mi N on Springhill, right (east) on Sypes Canyon Rd 3 miles. Near the end the road becomes gravel and curves right to the parking area. The trail (1100 in 3 mi) intersect the Foothills trail. Heavily wooded, gradual switchbacks, not very rocky at all. From there go right 3 mi to the M, some quite steep and some contouring, or left 4 mi to Middle Cottonwood mostly steep up or down or straight up (3,000 in 2 mi) consistently steep to Baldy, intersecting the Baldy Trail 500 and 1/3 mi prior to the top. Sypes to M and back is one of the earliest snow-free trails in the mountains, 4100 in 12 mi.
Middle Cottonwood Trail (driving 25 min, 15 mi). 3.5 mi on Springhill Rd, then follow FS signs to Middle Cottonwood trailhead, right 2 mi on Toohey Rd to end, short right on Walker Rd to end, left 2 mi on Saddle Mt Rd to end, left on decent Forest Service road 2 mi to Middle Cottonwood trailhead. This is a perfect trail for a dog as there is a creek most of the way. Lots of fun crossings and then the third tallest peak in the Bridgers at the end. The trail joins the Foothills Trail in 1.2 miles so you can expect steep most of the time. Stay on the Foothills trail 2.5 miles more to Bostwick Saddle where you can continue straight on a spur trail to the top of Saddle Peak, 9200 (mostly a trail-less scramble to the top). Rocky down low, then nice then shale on the final climb to Saddle. Trailhead to peak and back is 9 mi, 4,000.
Truman Gulch (driving 40 min, 23 mi). 3.5 mi on Springhill Rd, right 2 mi on Toohey Rd to end, left on Walker Rd 3 miles to Forswell Rd. Right about 3 miles, last 1. 5 mile is very rutted, impassable at times, mostly 4-wheel drive unless very dry. Trail intersects the Foothills Trail near a beautiful meadow in 1.5 miles on a mostly runnable, park-like trail. Probably the prettiest portion of the FH trail goes in both directions from here, particularly N to Ross Pass about 3 miles more. Ross Pass is so beautiful it should have been used in Sound of Music. Ross and back, 9 mi, 3200.
Corbly Gulch (driving 55 min, 26 mi). 8 mi to Springhill Community Rd, right 1 mi to Corbly Gulch Rd. Left 2 4 mi depending on how far you dare drive on this very rocky road. Park and run on up the road. 1.5 mi from closed gate, still on the old road, watch for a trail sign pointing left and down in a tall stand of pine trees. It is also possible to go right up a good trail at first, then deer trails to Sacajawea Peak but I recommend you first try the main trail to the left. This is a nice alternate route to the saddle between Sacajawea (9,400) and Hardscrabble (9,300) Peaks, unrelentingly steep with lots of occasionally deep creek crossings, even in August. 4000, 9 mi roundtrip to Sac. Nearly the same to Hardscrabble. Wettest trail in the Bridgers, especially in August.
North Cottonwood (driving 50 min, 28 mi). 11 mi on Springhill Rd. Watch for FS trail sign on right as you summit a gradual climb. No parking lot. The trail is a gradual climb in a heavily wooded gulch along a nice stream at first, intersecting the Corbly Trail just below the saddle to Hardscrabble and Sac (4 mi, 3000). The reward is a good chance of seeing goats on the high benches north of Hardscrabble in 3 4 mi. Interesting geography on these benches.