Platte County is a county located in the U.S. state of Nebraska. As of the 2010 census, the population was 32,237. Its county seat is Columbus. The county was created in 1855.Platte County comprises the Columbus, NE Micropolitan Statistical Area.In the Nebraska license plate system, Platte County is represented by the prefix 10 (it had the tenth-largest number of vehicles registered in the county when the license plate system was established in 1922).