Take 10021: Financier J. Christopher Flowers spent $46 million last year on a townhouse at 74th Street and Fifth Avenue. While nearby properties haven't commanded as much, it still takes double-digit millions to play in that Upper East Side neighborhood. Not so further east, between Second and York Avenues in the 60s and low 70s--an area called Lenox Hill--there are numerous high-rise condos and co-ops listed for between $300,000 and $550,000. Both neighborhoods share the same ZIP.
That's because ZIP codes, which were implemented by the Postal Service in the 1960s, were designed to handle the era's growing population and increased volume of business mail. The first number identifies the region, with zero being the Northeast and nine being the West Coast.
Numbers two and three identify the metro area, and the final pair specify the post office. Though often shorthand for neighborhoods, ZIPs don't change to reflect shifting neighborhood or demographic boundaries. The result? Our list is a bit slanted toward low-density enclaves like Alpine, where there are 333 people per square mile, as opposed to parts of Manhattan, where there are 45,800 people per square mile and a larger variance of home prices.
Though our list is heavy with ZIPs along the coasts, areas in the Midwest and South show up as well. Kenilworth, Ill. (60043), located along Lake Michigan's north shore, nabbed 19th place, as area home sales reached a median price of $1.66 million. Despite slumping sales across Arizona, Paradise Valley (85253) came in 35th at $1.41 million, behind a strong 236 sales. Sullivan's Island, S.C. (29482), Hatteras, N.C. (27943), Wrightsville Beach, N.C. (28480) and Great Falls, Va. (22066), are all, technically, in coastal states but were the only remaining non-Northeast, West Coast and Florida ZIPs in the top 100.
Methodology We based our rankings on each ZIP's median home sale price, between July 2006 and June 2007, as collected by First American CoreLogic, a national real estate data collection and research firm that tracks over 150 million parcels in over 3,000 counties, amounting to 99% of all real estate transactions. The data included all residential land transfers and all arms-length transfers; all sales noted were ones in which the buyer and seller were not the same and the transaction was greater than $3,000. Demographic information such as median income and population density are from the U.S. Census Bureau's 2000 American Community Survey, the most recent. Densities are measured on a persons-per-square-mile basis and are rounded up to the nearest whole person.