I-5 Colonnade in Seattle, Washington, United States, is a 7.5-acre (30,000 m2) city park underneath Interstate 5 connecting the Capitol Hill and Eastlake neighborhoods, which were divided by the freeway in the 1960s.

The trails were constructed by the Evergreen Mountain Bike Alliance (then known as the Backcountry Bicycle Trails Club) and its volunteers; Phase 2 construction was funded by the Seattle Neighborhoods Matching Fund and private donations.

More advanced trails include a hillside switchback loop, several jump lines featuring K-line and Nicks Kicks, Zeb's Grotto a trials riding area, an elevated structure section featuring Cyclone and The Octagon Of Death, a rock jumble descent named the Waterfall, and Downhill/Freeride lines including The Offramp, Holy Chute, and Pips Hips.

Using the available space under the I-5 freeway has been heralded as a highly innovative approach to bring mountain biking to the intercity environment.

The park transformed the area from a drug infested encampment to a refuge for Outdoor recreation.