It broadcasts classical music and news on five stations in the northwestern Lower Peninsula.
At one point early in the 2000s, IPR led the nation in annual listener support.
Originally broadcasting eight hours per day, it grew enough within a decade to become a charter member of NPR.
Interlochen bought contemporary Christian station WDQV in 2005 and converted it into a third satellite for the eastern portion of the market, WIAB.
In 2000, Interlochen signed on WICA at 91.5, and by 2001 all NPR news and talk programming moved there from WIAA/WICV.