Wilmer is a city in Dallas County, Texas, United States. The population was 3,682 at the 2010 census. It is part of the Dallas–Fort Worth–Arlington Metropolitan Statistical Area.Union Pacific's Dallas Intermodal Terminal is located partly in the city of Wilmer and partly in the city of Hutchins. The shipping facility, built by AUI Contractors, Prime Rail Interests and Halff Associates, was a 70 million U.S. dollar project.