A very easy path is the Trail of Two Forests, a brief boardwalk that takes you past the molds left when trees were immersed in lava flows 2,000 years ago. You can even crawl through two of these ancient impressions. The trail is right across from Ape Cave on Road 8303.

One of the most interesting hikes on the south end of Mount St. Helens is the 2.5-mile Lava Canyon Trail, which drops 1,400 feet along the Muddy River. This canyon was scoured out by a mudflow during the 1980 eruption, revealing sharp cliffs and five tall waterfalls. Although the upper end is wheelchair-accessible, the lower part crosses a long suspension bridge and then descends a cliff face by a steel ladder. Great for the adventurous, not fun if you have a case of acrophobia. Get to the trail by following Forest Road 83 nine miles (paved the entire way) beyond Ape Cave to the trailhead.

The Loowit System (No. 216) is a difficult 29-mile trail that circles Mount St. Helens and is accessible from trailheads on all sides of the mountain. Plan on three days to get all the way around, and be prepared for lots of up-and-down hiking and faint trails in places. Camping is available at various points along the way, but contact the Forest Service for specifics since some areas are off-limits.

For an enjoyable loop hike, head to the end of Forest Road 8123 on the southwest side of the mountain and the start of Sheep Canyon Trail (No. 240). This path climbs through old-growth forests and drainages that were ravaged by volcanic mudflows and into a flower-filled alpine meadow along the Loowit Trail before returning downhill on the Toutle Trail (No. 238), which connects to the Sheep Canyon Trail and your starting point. Total distance is approximately seven miles.

The Lewis River Trail (No. 31) follows along this beautiful river from the Curly Creek Falls to Lower Falls (a fun swimming hole), a distance of more than 10 miles. Between Curly Creek Falls and Lower Falls on Road 99 is Big Creek Falls, plummeting 125 feet into a pool that makes a popular place for a summer dip. Above Lower Falls, you can follow the road to a series of roadside falls, including the scenic Middle Falls and Upper Falls.