http://ngm.nationalgeographic.com/2011/02/geography/usa-surnames-interactive

This site is an exciting interactive map of surnames across the United States.  This helpful map displays the most common surnames in each area, with the larger bolder ones being the most common and the smaller ones being less so. Using this map it is easy to track many interesting pieces of information besides just checking the popular names around your home. One of the most interesting opportunities this site provides is the ability to see where different ethnic groups have settled around the United States. The prevalence of english and irish names in the mid atlantic, scandinavian names in the midwest, and latino names in the southwest states all point to very specific and fascinating settlement patterns. This is also shown in the identification of small subpopulations such as the cuban community in southern florida. This map also shows an interesting pattern of population density. As you might expect, names are much larger and more densely packed in the northeast, while the western states have fewer names, most of which are much smaller.  In making this map, National Geographic has used geography and cartography to portray information on surname distribution in a creative, accessible way.