There are 5 US Post Offices in Merrick County serving a total of 7,262 residents equating to 1,452 residents per post office. It's estimated that approximately 11,591 packages are handled across the 5 county post offices annually. Merrick County is a county in the U.S. state of Nebraska. As of the 2010 census, the population was 7,845. Its county seat is Central City. Merrick County is part of the Grand Island, NE Metropolitan Statistical Area. In the Nebraska license plate system, Merrick County is represented by the prefix 46 (it had the forty-sixth-largest number of vehicles registered in the state when the license plate system was established in 1922)."