The first thing Arizonans should know about Pittsburgh is that we don't share the same concerns.

Sunburn has never been our problem and we don't ever worry about water -- except when there's too much of it. One or more of our three rivers will want to come up over its banks every now and again, and so hustling to get your car off the parking lot at the Mon Wharf -- that's short for "Monongahela" -- before the water reaches the bumpers is a tradition almost as old as commuting itself.

You also may be aware that our populations have been moving in opposite directions for decades. Pittsburgh isn't a big city anymore, we just play one on TV. The city of Phoenix added more people in the 1990s alone than our current population, around 311,000. But Pittsburgh does have something new money can't buy: Heft.

That's the word a Coloradan I know used to describe Pittsburgh when he moved here. Heft. We've been knocked around plenty, but the evidence that Pittsburgh was once a much bigger deal -- Pittsburgh peaked in the 1950 Census at nearly 677,000 -- is everywhere you look: major universities and museums, opera, ballet, theater, a world-class symphony, great Victorian architecture and three professional sports teams, little of which we'd have if we had to start from scratch.

The real Pittsburgh, the Pittsburgh of the mind, extends beyond our city's freakishly small 56 square miles and into the suburbs of neighboring counties. You could even say, as E.J. Montini suggests, that Pittsburgh extends into all those Steelers bars dotting the country, the legacy of the great diaspora caused by the implosion of the steel industry in the 1970s and '80s.

We still make a little steel hereabouts, but the work is a faint echo of the boom times. Health and education drive the economy now. And here's a stat that might stun you: Even after losing more than half of our population, we still have more people per square mile than Phoenix.

No kidding, it's true. The city of Pittsburgh has more than 5,600 residents per square mile while Phoenix has just under 3,000.

The reason for this is you're cheating.

You see, here in Pennsylvania, we don't ever adjust our borders to reflect the modern economy. Back in 1950, Phoenix had just inched above 100,000 residents in its 17 square miles, but now you have more than 1.5 million people in a city of 517 square miles. You've gobbled enough land since World War II for a footprint nearly 10 times our size.

The Point here -- that's what we call the land at the confluence of the three rivers on the western edge of Downtown, the Point -- is that there's a genuine, walkable town at our core. The funky street grid was sketched on parchment by a military surveyor in 1784. (America had recently taken ownership from the British, who had snatched it from the French.) If we stretched our borders as far as yours we'd take in 900,000 people or so. You'd still be significantly larger, but we'd be looking more like brothers. Or cousins anyway.

We don't play that way, though. We've split our county more ways than a pizza in a homeless shelter. It's said there are 130 municipalities in Allegheny County, though nobody's entirely sure because people tend to get bored before they're done counting. But the county did have more police departments than Montana the last time anyone checked, and any time a small-town cop shop merges with, or is served by, a neighbor's, residents of the shrinking town scream for the heads of cowering council members. Very festive.

Oh, we talk about merging city and county from time to time, but nothing much happens because that would take time away from talking about the Steelers. And that could be our key difference. My scouting report suggests Arizonans retain an alarming ability to think of football as just a game.

I've never been to Phoenix, but I know people there. (Knowing someone who has moved to Arizona is almost as easy as knowing someone who has moved from Pennsylvania.) My friend the new Phoenician (a far cooler name than "Pittsburgher," I readily concede) told me about mid-day Tuesday, Arizona time, that he was standing in Arizona Center, your open-air mall, and had watched a couple of hundred people walk by, none of them wearing Cardinals jerseys.

You're thinking, so? Who would dress in football jerseys to go shopping on a Tuesday? About every eighth person in Pittsburgh, that's who.

There is almost no social situation where a Steelers jersey is frowned upon. Work. Church. School. Prom. The local desire to wear the names of other people on their black-and-gold backs can confuse newcomers. One reader called me earlier this month to say she'd just moved to Pittsburgh last summer and was working in a day care center where "every baby in the zero-to-3 group" wore Steelers paraphernalia on Fridays.

"It's like a cult,'' she said.

'Tis.

Kinship with the Steelers has something to do with their rocking through the '70s when the region was reeling. It has something to do with a common bond for a place and a people spread far and wide. But mostly, I think, it's because the team's so very good. It can carry us on its collective back through some otherwise miserable winters.