Country music's biggest stars and their legions of hard-partying fans are headed to the annual Country Jam music festival June 21-24 in Mack, located west of Grand Junction.This year, Country Jam officials have gone for broke with the lineup, signing up headliners such as the Zac Brown Band, Trace Adkins and Blake Shelton. When news of their festival appearance came out last November, Country Jam experienced the single largest launch date for ticket sales in its 21-year history. Also performing are country legends the Charlie Daniels Band, Luke Bryan who recently scored a No. 2 spot on the Billboards with "Tailgates & Tanlines," and Justin Moore who charted with "Outlaws Like Me." Come for the day or stay for all four days at the Country Jam campgrounds. Camping spots are going fast, and due to overwhelming demand, Country Jam is offering new this year "premier camping," 20-foot-by-30-foot sites located closer to the festival grounds.Purchase four-day or single-day general admission tickets at any Bradley petroleum convenience stores. VIP, reserve, general admission, campground and Country Club tickets are also on sale at countryjam.com or by calling 800-7800-JAM.