Red Willow County is a county located in the U.S. state of Nebraska. As of the 2010 census, the population was 11,055. Its county seat is McCook.
In the Nebraska license plate system, Red Willow County is represented by the prefix 48 (it had the forty-eighth-largest number of vehicles registered in the county when the license plate system was established in 1922).
Red Willow County was formed in 1873. It was named after the Red Willow Creek. The name is reported to be a mistranslation of the Dakota Indian name Chanshasha Wakpala, which literally means Red Dogwood Creek. The Dakota referred to the creek as such because of an abundance of the red dogwood shrub that grew along the creek banks. Its stem and branches are deep red in color, and it is favored in basket making.