The Sky River Rock Festival and Lighter Than Air Fair was a historic rock festival held on a raspberry farm on the Skykomish River outside Sultan, Washington. First held August 31 to September 2, 1968, it was the first multi-day outdoor hippie rock festival at an undeveloped site. The line-up included bands such as the Grateful Dead and Santana. The festival was held the next year on August 30 and September 1, 1969 in Tenino, Washington, and finally on August 28 until September 8, 1970 in Washougal, Washington.

On April 28, 1968, nearly 3,000 fans attended a rock concert at a farm in Duvall, Washington where an upright piano was dropped from a helicopter. Performances included Country Joe and the Fish. This concert is well-known to locals as the Piano Drop. This event inspired the Sky River Rock Festival and Lighter Than Air Fair which occurred later that year.

In 1968, the town of Sultan, Washington was visited by more than 20,000 hippies during the festival. Though the event was ticketed, many thousands of people showed up without tickets and snuck in. Proceeds were donated to the Mexican American Federation of Washington, the Foundation for American Indian Rights and the Central Area Peace and Improvement Cooperative. The Camlin Hotel hosted performers for the festival.

Billy Roberts played at the Sky River Rock Festival in 1968 and jammed with Big Mama Thornton, James Cotton, and members of the Grateful Dead.[6] His friend Dino Valenti was also on the bill. The line-up included Santana, Grateful Dead, The Youngbloods, Country Joe and the Fish, It's a Beautiful Day, The Peanut Butter Conspiracy, Muddy Waters, Buffy Sainte-Marie, John Fahey, guitarist Sandy Bull, Seattle psychedelic band Easy Chair and others. Also on hand was the young comedian Richard Pryor. Due to the muddy surroundings of the stage, Pink Floyd were unable to put up their gear and had to cancel the gig.

Colby Street performed with Sue Draheim (Tenino, Washington in 1968 and 1969), calling themselves "Dr. Humbead's New Tranquility String Band and Medicine Show". The band consisted of Sue Draheim, Jim Bamford, Mac Benford, and Will Spires.

Sky River III was held 1970 in Washougal, Washington. One of the longest-duration festivals, lasting 10 days from August 28 until September 8, with daily attendance in excess of 10,000 on some days. Over 40 bands were featured on the event posters.

In 1970 the nucleus of the Air Pirates cartoonist collective met at the Sky River Rock Festival. Bay Area residents Ted Richards and Bobby London met Shary Flenniken and Dan O'Neill at the media booth, where Flenniken was producing a daily Sky River newsletter on a mimeograph machine. Before the festival was over the four of them produced a four-page tabloid comic, Sky River Funnies, mostly drawn by London.

Sky River Rock Festival 1968

Sky River Rock Festival 1969

Sky River Rock Festival 1970