Wilmar is a city in Drew County, Arkansas, United States. The population was 511 at the 2010 census, down from 571 in 2000. Wilmar is located in western Drew County along U.S. Route 278, which leads east 8 miles to Monticello, the county seat, and west 8 miles to Warren. Arkansas Highway 133 leads north from Wilmar 7 miles to Arkansas Highway 35, east of Rye.