This is simply my own informal, ongoing list of wheelchair-accessible (or fairly accessible) paths and trails in and near the Portland Metro area.

Note: since I began this site (in 2010), the Intertwine has begun a map "featuring every park, trail and natural area the Portland-Vancouver region." One of their features is commentary on accessibility. Hooray!

More about this wiki.

Portland Metro area

Resources

The Access Recreation Project - working to develop uniform accessibility guidelines for PDX-area trails & outdoor recreational facilities

Freewheel - "the neatest gadget for manual rigid-frame chairs" (and getting them off-road), says Arwen

The Intertwine - An alliance of various entities in support of the network of parks, trails and natural areas in the Portland-Vancouver area

Portland Family Adventures - this virtual guide to regional family outings includes a useful section on bike/paved trails

Portland Parks and Rec - a list of parks that have "paths - paved"

Regional

Springwater Corridor

SE

Crystal Springs Rhododendron Garden - Paths to the central duck pond are paved but steep.

Eastbank Esplanade - an urban path overlooking the Willamette

Gresham-Fairview Trail (NE Halsey south to Springwater Corridor) 

Mt Tabor Park

Portland Memory Garden - a fully accessible garden designed for people with memory issues 

Powell Butte

Reed campus sidewalks & bridges

Tideman-Johnson Park  a very short loop & spur off the Springwater Corridor near the Johnson Creek Blvd. trailhead

N & NE

The Grotto ?

Kelly Point Park

Marine Drive bike path

Peninsula Crossing Trail

Pier Park - some paved sections on the perimeter

Smith and Bybee Wetlands

NW

Macleay Park

SW PDX (& Tualatin)

Cooper Mountain Nature Park ?

Cottonwood Bay Park ?

Elk Rock Garden at the Bishop's Close ?

Fanno Creek Greenway Trail in Tualatin

Hoyt Arboretum

Tryon Creek

Tualatin Hills Nature Park

Tualatin River National Wildlife Refuge near Sherwood

Vancouver

Burnt Bridge Creek Trail

Frenchman's Bar Trail

Salmon CreekTrail

Waterfront Renaissance Trail (an urban path, aka Columbia River Renaissance Trail)

South of PDX (Oregon City, Canby, Wilsonville, etc.)

Champoeg State Heritage Area south of Wilsonville

Clackamette Park near Oregon City ?

Graham Oaks Nature Park in Wilsonville

Mollala River State Park

Trolley Trail from Milwaukie to Gladstone (6-mile multi-use paved trail)

Farther out

Banks-Vernonia State Trail

Cape Horn in the Gorge (Washington side)

Catherine Creek   in the Gorge (on the Washington side, more or less opposite Mosier)

Foothills Park and Trail in Lake Oswego

Mosier Twin Tunnels (part of the Historic Columbia River Highway State Trail) - between Mosier & Hood River

Mount St Helens Visitor Center at Silver Lake - 5 miles east of Castle Rock (in WA)

Rock Creek Trail in Hillsboro

Viento campground to Starvation Creek waterfall (part of the Historic Columbia River Highway State Trail)

Wildwood Recreation Site near Sandy