DMA stands for Designated Market Area. A Designated Marketing Area represents a city and surrounding area within a certain region. DMAs are most commonly used by traditional medias like TV and Radio stations to clearly detail a particular market. Nielson designates 210 DMAs within the United States of America. When placing media for regional or national businesses, agencies will often target to reach a particular audience within a DMA (Males Age 18-44 in the Columbus Ohio DMA).