Willacy County is a county in the U.S. state of Texas. As of the 2020 census, its population was 20,164. Its county seat is Raymondville. The county was created in 1911 and organized the next year. Willacy County comprises the Raymondville micropolitan statistical area, which is included in the Brownsville-Harlingen-Raymondville combined statistical area, which itself is part of the larger Rio Grande Valley region.