The Big Float was an annual July celebration of the Willamette River in Portland, Oregon, United States.

[1] Established in 2011, as a benefit for the Human Access Project, attendees formed a giant people-powered flotilla and beach party to encourage Portlanders to reclaim the Willamette River for swimming and other aquatic recreation.

[5] The Human Access Project (HAP), under the leadership of Willie Levenson, started the Big Float in 2011 to give Portland residents positive interactions with the Willamette River.”[1] The name for the event came from Portland's Big Pipe project — a 20-year undertaking that was completed in 2011.

It entailed the overhaul of the city's wastewater system to divert sewage from flowing into the Willamette River and the Columbia Slough.

[8][9] Since inception some 25,000 people have participated using tubes, kayaks, or flotation devices to drift half a mile downriver.