Romulus is a city in Wayne County in the U.S. state of Michigan. The population was 23,989 at the 2010 census. Romulus is a western suburb of Metro Detroit and is also considered part of the Downriver collection of communities. It is most notable as the location of the Detroit Metropolitan Airport, a major hub for Delta Air Lines.

Wayne County is the most populous county in the U.S. state of Michigan. As of 2020, the United States Census placed its population at 1,793,561, making it the 19th-most populous county in the United States. The county seat is Detroit. The county was founded in 1796 and organized in 1815. Wayne County is included in the Detroit-Warren-Dearborn, MI Metropolitan Statistical Area. It is one of several U.S. counties named after Revolutionary War-era general Anthony Wayne.