Walnut Ridge is a city in and the county seat of Lawrence County, Arkansas, United States. The population was 5,098 at the United Sta…Walnut Ridge is a city in and the county seat of Lawrence County, Arkansas, United States. The population was 5,098 at the United States Census's 2019 estimate. Walnut Ridge lies immediately north of Hoxie. The two towns form a contiguous urban area with approximately 8,000 residents. Williams Baptist University is in College City, a formerly separate community that merged into Walnut Ridge in 2017.