Median home value: $3,406,640
YOY price change: -14.5%
Population: 582
2010 Rank: Unchanged

Southampton's ritzy village of Sagaponack maintains its rank as the country's most expensive small town in 2011. The village, which covers eight square miles, has been home to musician Billy Joel, Apollo Management Chief Operating Officer Henry Silverman, and former Kinray Chief Executive Officer Stewart Rahr. It is also the site of Fair Field, the 63-acre oceanfront estate of Renco Group Chief Executive Officer Ira Rennert, who owned military Humvee maker AM General. At 66,000 square feet and with a 164-seat theater, three swimming pools, and a two-lane bowling alley, Fair Field is one of the largest private houses in the country.

See the Zillow Home Value Index for Sagaponack, N.Y.

(Editor's note: This slide has been updated to correct the dimensions of Fair Field.)