Trails Farther Afield of the Rose City

Note: Where multiple videos are listed together, these are the same video in different formats. Smaller just means slightly less quality but also less gandwidth required.

Columbia Gorge - under 1 hour East of Portland

Larch Mountain - A short but very fun rocky/rooty downhill (1000ft descent), followed by a loooong climb back up. Some great views of the surrounding area from the very top (see this page for a 360-degree view from Larch Mountain). Be careful about directions! (click on the picture for more details)
Warning: there are three trails within an hour or so of Portland named Larch Mountain!
There should be some trails at the bottom of the gorge, but the NPS has removed their information.

Hood River Area - 1.5 hours East of Portland

There are some classic trails south of Hood River. Discover Bicycles provides some good descriptions, and you can buy a map at the shop. Check with them before heading out here early in the season; there may be snow or significant windfall. This is likely the best riding in the area. I don't have trail descriptions mostly due to my location.
Second Warning: If you visit early in the summer, the trail may be under snow or there may be many downed trees (see example here). The one time I rode there, we ended up carrying the bikes a lot.

Videos
12.5MB Windows Media
6.3MB Windows Media

Henry Hagg Lake - under 1 hour West of Portland

A fairly easy ride that bobs up and down a lot of small hills (newbies may find the hills rather tough, though). The part between the dam and boat ramp A does have some fair-grunt climbs, so a good newbie ride is an out-and-back north from Boat Ramp A to the point where the trail dead-ends at paved road. There is also an outlet to the pavement a couple miles into ride - that's not the end. The very north end (as well as the dam) has no trail, so you have to ride a few miles on the road to make a full loop around the lake (about 14 miles). The trail always follows just inside the road, so its easy to make it back to the car at any point. A map and directions to the trail can be found here.
Videos
5.15MB Windows Media

Tillamook State Forest - about 1 hour West of Portland

Getting There - West on Hwy 6, four miles past the Tillamook Forest sign. Gale's Creek is on the right side of the road; the gravel road to the campground is clearly marked. Brown's Camp is 1/2 mile further; the road to the parking area is next to the big gravel pile with the brown barn.

Brown's Camp - Also called "Nels Rogers", "Historic Hiking Trail". This is excellent riding not too far from Portland. Good technical singletrack - roots, rocks, etc. Be sure to stop by University Falls, especially early in the year when its really flowing. I'll try to get a map online at some point, as its kind of easy to get lost here. There is a maze of fireroads that makes this a good choice for evening rides (you can get back to the car really fast), as long as you don't take a wrong turn in that maze! The "historic hiking" trail is just one big loop, though.

Gale's Creek - A fairly new, developing set of trails north of highway 6. There is a blazing downhill that starts just east of the Brown's Camp entrance off Hwy 6. It can be accessed by climbing the gravel road up from the campground (then turning right and riding west on Hwy 6 for a few miles). Gale's Creek trail meanders along the creek, and provides some fun climbing. It ends at a "T" junction - left is Storey Burn, right is Bell Camp. Both climb up to a fireroad, but their trailheads are many miles apart, and I'm not sure the fireroads even intersect (so there's no loop opportunity there). Story Burn is a long climb. Bell Camp is a long climb that eventually becomes outrageously steep - some sections are difficult to even walk up. Story Burn can be used as a loop for that first downhill, but I prefer to just turn around and blast back down. There is a fireroad that can be ridden up to Bell Camp but I haven't figured it out yet.

Mollala River Corridor - under 1 hour Southeast of Portland

I've only riden this once, and all I found was fireroad and a small bitof really mushy, muddy singletrack. But other people seem to like it.