Walnut Ridge is a town located in the U.S. state of Arkansas. It is within and the county seat of Lawrence County. It has a total area of 16.01 square miles at 36°4′21″N 90°57′25″W. The elevation is 269 feet above sea level. As of the 2010 census data, it had a total population of 4,890. The population density was 291.92/sq mi. Estimated per capita income in 2016 was $19,754. It has Zip code 72476.