The June 21 show will benefit the Asheville nonprofit, which helps indigent people with legal services.
The jam went deep into the night Saturday.
Warren Haynes joins the Doobie Brothers, plus tunes by Dawes, Blackberry Smoke, Bruce Hornsby and more.
More acts will be announced in coming weeks.
Keith Hornsby recently scored a career-best 26 points in a game against Ohio State.