KMZ file (6..6 mb) of nearly 7,000 neighborhood boundaries in the largest cities in the U.S.

The geographic boundaries are made available in shapefile format by Zillow.com under a Creative Commens License.

State- by-state shapefiles are available here:

http://www.zillow.com/labs/NeighborhoodBoundaries.htm

For faster load time, Google Earth initially displays boundaries and labels for Arizona only.Click on the sidebar boxes to display additional states.

Neighborhood boundaries are demarcated by broad green lines. To colorize the neighborhood areas, right click on "ZillowNeighborhoods-AZ" (or another state) in the sidebar, then "Properties",then "Style", and check "Random" under the Area item.

CTRL-Click on the map to display the region ID in addition to the neighborhood name.

Jan. 18 -- updated so that labels are sorted by city and state.

At some point, I may update the file to include socioeconomic data estimates from the SF3 file of the 2000 census.