Rebecca Snyder couldn't believe her ears -- and it turns out she was right.

"There should be something left!" she said.

The latest batch of survey data from the U.S. Census Bureau purport to show that there isn't a single home in all of Apple Valley that was built before 1940.

Once the research librarian for the Dakota County Historical Society poked around on computers giving the date of birth of every home in the county, she was able to turn up seven older places. A pair of them date to the 1890s: the homes at 7001 W. 130th St., just off Galaxie Avenue, and 14501 Galaxie.

But the survey does point to something very real about Apple Valley that distinguishes it from lots of other south-of-the-river communities.

"There really are not that many properties there built before 1960," much less before World War II, she said. "And several of those were 1957 or '58. Apple Valley just plain didn't take off till the Sixties."

The census bureau's survey, then, is both illuminating and not to be taken as gospel truth down to the last decimal point.

The latest results were released last month for even the tiniest communities, based on surveying done over the past five years, ending in 2010.

The surveys' value is that they cover topics no longer covered by the main census, which has been throttled back to just a handful of questions: age, race, home ownership and a few others. Plus, surveying is done constantly, not just every ten years.

So what portrait is it sketching?

SOCIO-ECONOMICS

The teensy-weensy enclave of Sunfish Lake emerges with the most upscale south-of-the-river demographics, partly because it's so small that there's no one offsetting the high end with anything more modest.

About two-thirds of its homes are reckoned to fall into the census's biggest-home category -- nine rooms or more -- and that's nearly twice the share of the next-closest competitor, Mendota Heights.

Tiny Coates, on the other hand, not all that far away, represents the opposite extreme, with some demographic indicators that peg it even lower than the mostly trailer-park communities of Hilltop and Landfall, elsewhere in the metro. The share of Coates residents in management, science or the arts is by far the lowest in Dakota or Scott counties, while Sunfish Lake is markedly higher than any other community in those counties.

Yellow light, though: The margin of error for such tiny places is large.

Another way of thinking about wealth is which community has the largest number of high-income households. In the census, the top category is an annual household income of $200,000 or more. By that measure, the richest communities south of the river are Eagan (about 2,100 such households) and Lakeville (about 1,400). Only Eagan cracks the metro's top ten in that department; it comes in ninth, way behind peers such as Plymouth, Edina and Eden Prairie.

COMMUTING

Travel time to work is a measure of both how far a community is from the main job centers and how many jobs there are right in town.

Thus, places on the geographic fringe such as Randolph or Belle Plaine have commutes that are half again as long -- half an hour each way, on average -- as the 20 minutes experienced by close-in suburbs. But once you get far enough out (think Northfield) you start reaching places where a lot of residents work in town, and then commute times drop off drastically.

ANCESTRY

Irishness is one of the mild surprises in the census, for those who imagine that a place like Rosemount with its heavy stress on its Irishness ("Home of Irish Nation") must be a massive enclave of O'Malleys.

Rosemount barely cracks the top ten even in the south metro, with an Irish quotient that's only about half that of some of its neighbors.

If it's any compensation, though, fully 18 south-metro suburbs and exurbs are more Irish than St. Paul (12 percent), which many still think of as the capital of Irishness in the Upper Midwest. As the Irish suburbanized, the Woodburys and the like became much closer to that status than the central city, which became home to new waves of immigrants.

HISTORY

A sharp distinction emerges between towns that have been robust communities for ages, and those that developers more or less created out of farm fields within the living memory of the average baby boomer.

Even though Jordan grew rapidly during the hypergrowth years that followed the opening of the Bloomington Ferry Bridge, for instance, fully 15 percent of its homes still date from pre-1940, meaning it has a substantial older housing core.

In contrast, the whole swath of suburbs from Eagan and Rosemount to Prior Lake and Savage has only a light smattering of older homes -- not many more in fact than Apple Valley -- the creation of a single developer, Orrin Thompson Homes.

David Peterson • 952-746-3285