The object of this quiz is to click on the circle containing the largest population. When you begin you'll be shown 2 circles on the map with radii between 10 and 250 miles which do not intersect. Click on the one with the larger population within it (based on US census tract info) then 'Submit' - if you are correct you'll move on. One incorrect round and the quiz is over. Every 5 rounds the number of circles on the map will increase by 1. Try to build the longest streak of correct circles. Circles displayed will always be non-intersecting.
NOTE: You may have to zoom out to see all circles, occasionally a AK/HI circle will be included. Also, only population within the US is included in the total, any Canada/Mexico coverage counts as 0 population within the circle.
Quiz Takers 
Updated – welcome new CSA’s since 2023!
This quiz doesn’t make much sense. “Combined statistical areas” based on what criteria? These are clearly not based on metropolitan areas. Just speaking of the western US: There’s nothing for San Diego/Carlsbad CA, Bakersfield/Visalia, CA, Santa Rosa/Napa, CA, Flagstaff, AZ, St George, UT, and whatever that thing is on the map in western Colorado is mostly rural and ski resorts, and doesn’t include Grand Junction. And there’s all kinds of cities in Texas missing from the list. It seems like a five year old decided what should be included here, and not.
CSA based on the OMB’s definition which the census uses (see directions).
Why isn’t Phoenix on this quiz?
Well, I think it’s basically because Phoenix isn’t a CSA. As to why, I think it all bows down to the criteria used by the guys who think this stuff up. San Antonio and Austin for instance aren’t there either.
Yeah. Five major metropolitan areas aren’t considered CSAs: San Antonio, Austin, Anchorage, Honolulu and Phoenix.
I see two cities of over 1,000,000 people, three state capitals and three largest cities in their states in those five.
And that doesn’t take Laredo, Billings and Sioux Falls into account!
You can add San Diego and Tampa-St Petersburg to that list.
Louisville now added to this list that makes no sense whatsoever