The population of the southwest Iowa town of Saint Charles is officially 653, but that’s swelling this weekend by many times over.

The 5th annual Hinterland Music Festival is opening this (Friday) afternoon and runs through Sunday in the Madison County town, just 12 miles east of Winterset. Based on pre-event ticket sales, organizers predict there will be more then 20,000 in attendance from all over the U.S. and at least nine other countries.

There are 22 scheduled acts, with headliners including: Brandi Carlile, Jason Isbell and The 400 Unit, Maggie Rogers and Kacey Musgraves. It’s billed as a music and camping festival, curated for people who love both music and the outdoors.