From the Twin Falls trailhead, parallel the river and climb a tiny hill. Look for trillium on the river side of the trail in the spring. Avoid the social trail that is visible going down to the water; there are better places to get to the river ahead.
Head down a steep, but short hill to a swampy area. In spring it's full of skunk cabbage and in summer, salmonberries. Cross a short bridge and stay on the main trail, you'll arrive at your first river access just off the trail.
In this pool boulders separate the main current from the shallows. The pool is full of little fish and often dogs chasing sticks. During the record floods in 2006, the gauge upstream showed 9,000 cfs (cubic feet per second), and the trail beside the river was completely destroyed. Today, you can see the undercut bank and imagine how high the river was.
Flooding also did damage to this trail in 2014, but it has since been repaired and hikers can now access the entirety of the trail.
Climb away from the river, through the woods, to a large rock reminiscent of a turtle at the base of a decent sized hill. Up the hill are a series of switchbacks. Though it may be tempting to take a shortcut, make sure you stay on the main trail to limit your impact on the park.
It's here the climbing begins in earnest. When you come to The Benches you've completed the first hill and are rewarded with a partial view of the Lower Falls. It's often blustery at the Benches as North Bend's infamous wind slams into the hill, so bundle up if you think you may stop here.
This provides a good stopping point if necessary, but you're not too far from the main attraction. If you decide to continue, descend a couple hundred feet to the bottom of the hill, on the newly rebuilt trail (as of 2016) that bypasses a slide. At the bottom of the hill you'll find the Big Tree. The fence has collapsed, but stay back from the base. Soil compaction can harm the ecosystem around the ancient tree.
The trail begins to ascend the second hill, switchbacking gradually to another summit, and then a set of descending steps lead to the best view of the Lower Falls you can get. It can be crowded, but it's worth the 104 steps on the way back up. Remember to yield to uphill climbers, especially on the stairs.
You're nearly to the falls, but first you'll navigate a final set of stairs down to the Big Bridge. From the bridge you'll have great views up and down the valley, including the two cascades upstream. (Yes, that makes three separate waterfalls that are collectively known as "Twin Falls.") A few more stairs and another steep slope will get you to the upper overlook for a better view of the Upper Falls.
You can continue about another mile up the trail to join the John Wayne Trail and the Homestead Valley Trailhead, but it climbs into the trees and above the freeway. The trail never returns to the river beyond the bridge and traffic can be loud.
Since the trail is at the bottom of the valley for most of its route and the trees limit long views, hikers get to focus on the nature nearby. Look for walls of maidenhair ferns, flowers blooming throughout the spring and early summer, and evidence of the herd of elk that lives in the area.
If you're beginning your hike from the Homestead Valley trailhead, hike along the Iron Horse Trail for about a third of a mile before coming to a junction with the Twin Falls Trail. Switchback down hillsides and through lush green forest, until you arrive at the beautiful falls and the Big Bridge.