A media market, often called a Designated Market Area (DMA) in the U.S., is a geographical region where the population receives the same or similar television and radio programming. These markets are crucial for audience measurement, compiled in the United States by Nielsen Media Research for both television and radio, especially since its acquisition of Arbitron in September 2013. Additionally, the Federal Communications Commission (FCC) defines Television Market Areas (TMAs) for regulating broadcast, cable, and satellite transmissions, including "must-carry" rules.

Markets are typically named after their largest city but can have complex, multi-named designations or unusual shapes due to geography, sometimes overlapping or subdividing large metropolitan areas. Radio markets are generally smaller than their television counterparts due to stricter broadcast power restrictions. This detailed audience data, often segmented by demographics and psychographics, is vital for advertisers to effectively target specific groups.