This village and Garden City have been municipal neighbors for decades, one stop away from each other on the Long Island Rail Road, a four-minute ride. But despite their shared boundary, they are worlds apart.
Garden City is home to many executives. It has a median family income of $120,305, houses that look like pages out of decorator magazines, downtown businesses like Saks and Fidelity Investments and a population that is 92 percent white. The mayor and village and school board members are all white.
Hempstead is a working-class community. It has a $46,675 median family income, midrise apartment buildings, generic middle-class homes, a downtown with storefront churches, thrift shops and Spanish restaurants, and a population that is 51 percent black and 32 percent Hispanic. The mayor is black, as are all but one of the village and school board members.
Such separation of blacks and whites is the rule, not the exception, across Nassau and Suffolk Counties, so much so that a new study comparing rates of integration in different communities ranks Long Island as the nation's most segregated suburb.
''African-Americans have faced isolation far more than any other group, especially on Long Island,'' said David Rusk, an international consultant on urban and suburban issues who analyzed the segregation patterns. Other minority groups are more integrated, the figures show.
Erase Racism, a year-old nonprofit group sponsored by the Long Island Community Foundation in Jericho, hired Mr. Rusk to research the study and present it at a conference in Islandia on Wednesday. What he finds is a new version of an old problem.
The central finding is that 74 percent of Long Island's blacks would have to move to be evenly dispersed across the population. Mr. Rusk drew his conclusions from an analysis of the 2000 federal census by the Lewis Mumford Center for Comparative Urban and Regional Research at the State University of New York at Albany.
Segregation is far more extreme on Long Island, for example, than in two major Washington suburbs. In Montgomery County, Md., 41 percent of blacks would have to move to be evenly distributed. In Fairfax County, Va., the figure would be 38 percent. The nation's 100 largest metropolitan areas average 60 percent. The only places more segregated than Long Island are big cities like Detroit at 85 percent, Milwaukee at 82 percent and Chicago at 81 percent.
''It's almost like a township in the South African sense'' during apartheid, said another expert, Andrew Beveridge, a Queens College sociologist who has made similar findings.
Why Long Island is segregated is a matter of debate. Mr. Rusk blamed the tax, zoning, housing and education policies of Long Island's ''frustrating maze of little-box governments: 109 villages, towns and cities and 129 school districts.''
''The unspoken agenda of most little-box councils, or most little-box school boards, is 'to keep our town, or our schools, just the way they are for people just like us,' whoever us happens to be,'' said Mr. Rusk, a former mayor of Albuquerque. ''The result is that Long Island is highly divided by race and ethnicity. For black residents, Long Island is the most segregated suburb in America.''
Segregated patterns are continued in various ways, said V. Elaine Gross, director of Erase Racism, a group of business and community leaders that tries to foster integration on Long Island. ''Testers show that we still have racial steering and blockbusting going on,'' she said. Blacks often have a hard time getting mortgages, even with good credit histories, and are victimized by exorbitant charges, she said.
Correction: June 13, 2002, Thursday Two pictures on June 5 with an article about a study of segregation on Long Island, intended to contrast the largely black village of Hempstead with the mostly white community of Garden City, were published in error. The top picture, which showed housing near Nassau Community College, was made in East Garden City, not Garden City. The bottom picture, of a row of houses with porches, was made in Garden City, not Hempstead.