Combined Statistical Areas by Area in Square Miles

[Steely Dan]

Originally Posted by Yuri

UAs change every single day, literally.

No they dont, they get defined once every 10 years based on the decennial counts.

And they're based on census tracts which, while not quite as static as counties, still tend not to change a whole lot.

CT's are just a much smaller unit, and the UA measures something completely different (and more meaningful, IMO) from MSAs.

[Yuri]

Urban areas and metro areas are different concepts and they both have a purpose.

Administrative divisions matter as they shape people’s lives in lots of ways. A person living in Lake County inside the UA and other outside of it don’t live dramatically different lives. That’s why metropolitan areas are vastly more used than urban areas everywhere in the world.

The smallest universal administrative unit in the US is a county and that’s why they used them as the base for their metro areas (MSA and CSA) definition. They only happen to be bigger. In France, the smallest unit is the commune and they have 16 km2 on average; in the contiguous US, counties have 2,400 km2 average. But as you showed for Chicago and I for Los Angeles, population for urban area and metro area are virtually the same.

Counties size doesn’t make US metro areas to be oversized population wise.

[Steely Dan]

Originally Posted by Yuri

Counties size doesn’t make US metro areas to be oversized population wise.

But it does make their land area and population density values utterly meaningless.

Chicagoland does not sprawl across 7,000 or 10,000 square miles of land in any real world functional sense.

The combined area of 2,500 square miles of the Chicago UA + Round Lake UA + Kenosha UA is millions of times closer to reality.

[Yuri]

Originally Posted by Steely Dan

But it does make their land area and population density values utterly meaningless.

I totally agree. And that's why an angel dies every time one mentions the size of a metropolitan area and worse, bring density info.

Originally Posted by Steely Dan

Chicagoland does not sprawl across 7,000 or 10,000 square miles of land in any real world functional sense.

The combined area of 2,500 square miles of the Chicago UA + Round Lake UA + Kenosha UA is millions of times closer to reality.

If you want to discuss urbanized footprint and specially density, UA is the best way to go. But metropolitan areas must rely on fixed administrative borders because they are more complex organisms, involved on urban planning, often defined by commute rates or even is politically organized.

So if Oswego (Kendall) is inside Chicago metro area, Big Grove (Kendall) is too.