Willamar is a census-designated place in Willacy County, Texas, United States. It was founded in 1921 and named for its founders, Will Harding and Lamar Gill. The population was 15 at the 2000 census. Willamar apartments for rent comparison page shows most up to date rent information on Willamar apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.