As a people, Americans tend to cluster together.

Half of the U.S. Population Lives in these 146 Counties

Source: Business Insider

Marked in blue are the 146 counties with the most people out of more than 3000 counties in the whole country. (The country is now 81 percent urban or suburban.)

California, Texas and New York have the largest economies of any states (in that order). Together the three states produce more than a quarter of the country's GDP. Thus the 6 senators from the most productive states face 94 senators from less productive states.