WGCA-FM serves an area of Missouri with what population?
WGCA-FM:  The station airs a Contemporary Christian music format, and serves the areas of Quincy, Illinois, Hannibal, Missouri, and Keokuk, Iowa. Hannibal, Missouri:  According to the 2010 U.S. Census, the population was 17,606, making it the largest city in Marion County.
17,606