Google AdWords Learning Center - Customized Targeting

Customized targeting is best suited for advertisers with an audience in very specific areas. If you select the customized targeting option for your campaign(s), your ads will only appear to customers searching for results within (or located within) a specified distance from your business or within the area you define.

Additionally, customized targeting doesn't limit you to the cities and regions offered by region and city targeting. For example, an advertiser owns a restaurant chain in Southern California. With customized targeting, the advertiser could choose to target the entire southern half of California instead of specific regions or cities.

When setting up customized targeting, you have three options: enter a physical address, select a point on the map, or enter multiple latitude and longitude points to form a polygon.

Enter a physical address: With this option, you enter a street or business address. (This option is available for the U.S and Canada only.) You then choose a distance (such as 50 miles or kilometers) that forms the radius of a circle around the address. Only users located within this circle, or those who include in their search the names of cities within this circle, will see your ads.

Select a point on the map: Instead of entering an address, you can define the center of your advertising circle by dragging the interactive map to place a red marker on your location. This location will automatically be converted to exact latitude and longitude coordinates, which the AdWords system will use in targeting your advertising.

Multi-point (or polygon): Multi-point targeting lets you click three or more points on an interactive map to outline the advertising region of your choice. (Again, the system will convert the points you select to latitude and longitude automatically.) Using multi-point targeting, you can create target areas of virtually any size and shape.