Greenway is a city in eastern Clay County, Arkansas, United States. The population was 209 at the 2010 census. In 1876, W.V. Turner, a physician, established a post office known as "Clayville" in what is now Greenway. The name was changed to "Greenway" when a railroad line was constructed through the community and a depot was built. The origin …Greenway is a city in eastern Clay County, Arkansas, United States. The population was 209 at the 2010 census. In 1876, W.V. Turner, a physician, established a post office known as "Clayville" in what is now Greenway. The name was changed to "Greenway" when a railroad line was constructed through the community and a depot was built. The origin of the name "Greenway" is uncertain.