Any creek worth mentioning in the Bitterroots has a trail up it, and nearly all are worth considering for a hike. (A few trails burned in the huge Bitterroot fires of 2000, but most were spared.) But if you have only a day to spend in the lower Bitterroots, consider one of the following.
A largely overlooked long day hike (or unstressful overnight trip) that’s close to Missoula  leads up the Sweeney Creek drainage to Peterson Lake. Forest Service roads (turn west on Forest Service Road 1315 two miles south of Florence) will take the hiker most of the way up the canyon wall to a trailhead. After a couple of miles of easy traversing, the trail drops to alpine lakes, with the car having done most of the climbing.
Another popular ascent of intermediate challenge involves climbing St. Mary’s Peak. Again, this hike boasts a trailhead midway up the mountain, and one of the great views that the peak affords is onto the local lookout tower. From Highway 93, go two miles south of the Stevensville turnoff. A brown sign promising St. Mary’s Peak points up the switchbacks of Forest Service Road 739. The trailhead is about 10 miles from the highway, and it’s a 4.5-mile hike to the lookout.
Between Victor and Hamilton , at the crossroads hamlet of Corvallis, turn west to reach the Mill Creek trail. It’s about three miles in along a great trail to a waterfall; if you want to make a backpacking trip out of it, keep going for another 11 miles to a high mountain lake. This trail was damaged by the 2000 fires but has had lots of work since then.
Also damaged by the massive 2000 Bitterroot fire was the trail up lovely Blodgett Canyon, west of Hamilton. It’s now a good place to see wildlife and regenerating plant life. Hike the 1.5-mile (one way) Blodgett Overlook Trail for an overview. There are also good views of the valley on the drive to the trailhead. From Hamilton, head west on Main Street to Blodgett Creek Road (Forest Rd. 736), then turn left onto Forest Road 735; the trailhead is about five miles from town. To hike up the canyon itself, follow Blodgett Camp Road and make a right onto Forest Road 746; follow the trail 1.5 miles to a nice pool or eight miles to Blodgett Lake.
The Lee Metcalf National Wildlife Refuge is a good place for short hikes along the Bitterroot River. This riverside refuge is full of ospreys, eagles, and whatever migrating birds need a place to spend the night. White-tailed deer and coyotes also live here. In the summer, after nesting season, a two-mile loop trail is open through the refuge. Two shorter trails are open year-round, and picnics are encouraged. From the East Side Highway (Hwy. 269), watch for the binocular signs indicating a sanctioned wildlife-viewing area, either just south of Florence or just north of Stevensville.