Six-figure ZIP codes

Turns out, the zigzag of the ZIP code map can deliver a lot more than the mail.

Figures released by the Internal Revenue Service reveal which neighborhoods have the highest membership in the six-figure income club -- and which are mostly shut out.

On the social register are some curious couplings. For example, the high rollers in downtown high-rises share a ZIP code with the restaurant workers of Chinatown's low-slung rowhouses. In the 02111 address that's home to both groups, 20 percent of filers make at least $100,000 , nearly double the citywide average of 11 percent , according to 2004 tax filings (the most recent IRS data available) plotted by address via ZIP code.

The biggest concentration of $100,000-and-more earners in the Boston-Brookline-Cambridge-Somerville locale can be found in the realm of 02110, around the wharf district, where 47 percent of filers top six figures. Coming in second, at 39 percent, are the folks from Beacon Hill and the parts of downtown in the 02108 ZIP.

Alas, even with 20 percent of Harvard Square's hallowed 02138 residents raking in 100k or more, that ZIP code has to take a back seat to Brookline's prestigious 02445 tracts, where fully one quarter of the residents are in the $100,000 or plus crowd. That's almost twice the state average of 14 percent . One numeral up, in Brookline's 02446 that takes in citified Coolidge Corner, 20 percent of all filers find themselves in the $100,000 or over tax bracket.

Just across the border, Allston's funky 02134 contingent of students, musicians, immigrants and others clock in at only 3 percent. (Statewide, by the way, the average filer's adjusted gross income in 2004 was about $63,000.)

And that's just a sampler. For a deeper look at the area's pockets of money, check out the map or view the tax return information on a zip code chart. Take your time. Even if you still have to finish your own 2006 tax return, there's a little extra breathing room. This year, the filing deadline looms on Tuesday, the 17th, a delay from the usual 15th due to the Patriots Day holiday.

Authorities expect that of the 3.1 million returns to be filed statewide this season, about 181,000 of them will be late, according to Peggy Riley , IRS spokeswoman for New England.

For members of procrastination nation, time spent perusing the tax map or looking over the chart could provide another excuse to forestall the inevitable.