What is a DMA code?

The Wikipedia says:

A Designated Market Area (DMA) is a group of counties in the United States that are covered by a specific group of television stations. The term was coined by Nielsen Media Research, and they control the trademark on it. There are 210 DMAs in the United States.

Breaking your stats down by DMA is helpful if you are running a TV or Radio campaign. By telling you how much traffic you are getting from a certain DMA, you will be able to get a better idea of how your print, radio or TV campaign is performing.

Each DMA has a 3 digit numeric code. For example, New York, NY is also known as 501. Los Angeles, CA, on the other hand has been assigned the number 803.

To view the DMAs in order of size, see the Neilsen rankings.

Read the full WikiPedia article.