I had a great run today on the Eagle Creek/Tanner Butte Loop in the Columbia River Gorge. Starting at the Eagle Creek trailhead the route is more or less uphill for the first 14 miles and downhill for the final 11 miles or so. There are many opportunities to take short side trails to scenic locations. There is also a 1/4 mile scramble up to the top of Tanner Butte, though you may not see anything once you get to the top if it is a cloudy or rainy day.

Many thanks to @sarah430 for suggesting this wonderful loop.

Route information

Note: This information describes the route when starting from the Eagle Creek trailhead.

Type: Loop

Distance: 25+ miles

There are many side trails, including a scramble to the top of Tanner Butte. If you do the loop without any side trails the total distance is around 25 miles.
Two different GPS watches yielded two different distances, and there are varying routes near the end, hence the vague distance totals here.

Difficulty: Difficult

  • This is a difficult run and probably not well-suited for a beginning trail runner.
  • There is a lot of climbing on technical trail.
  • Very rocky in some sections, particularly in the first 6 miles.
  • Big, vertical drop-offs (exposure) in the first 6 miles.
  • There is safety roping in the gnarly sections.
  • Some drop-offs are 100-200ft.
  • Potential for quite a bit of over-growth on the trail near the top of Tanner Butte.
  • This is bear country, Yo.

Views

This is a beautiful run. The first seven miles of this run are simply gorgeous as you pass by countless waterfalls in beautiful country. Your climbing efforts will be rewarded around the 6.5 mile mark when the trail goes directly behind Tunnel Falls (pictured). It is pretty amazing.

Tunnel Falls

Misc

  • There are creek crossings. A couple of them could get you soaking wet if you end up in the drink.
  • If you are afraid of heights you will poop your pants.
  • It's pretty darn remote when you get near the top of Tanner Butte. Go prepared.

Directions from Portland

  • Take I-84 East to Exit 41
  • Turn right at the stop sign
  • Stay right and continue up the road a quarter mile or so to the Eagle Creek Trailhead
  • Park in the lower parking lot if you're worried about car break-ins