The United States has 3007 counties. The top 100 by population (3.3% of counties) have a total of 129 million people (40% of US population). The map above displays these top 100 – those colored orange are counties with more than 1 million people and those colored green have less than 1 million people. The cut-off population to be in the top 100 is 626,000 people. There are 39 counties with more than 1 million people and only 14 with more than 2 million people. A third of US States do not have one county in the top 100 and only 14 States have at least one county over 1 million people – CA: 9, NY: 7, TX: 5, FL: 5, PA/OH/MI: 2 each, IL/AZ/WA/NV/MA/VA/UT: 1 each.