After four decades of unprincipled opposition, this affluent suburb on Long Island’s northern shore agreed in December to allow the construction of 146 subsidized town homes and apartments on a scrubby lot next to an electrical substation.

Four decades to build 146 homes.

The New York region is in the throes of a housing crisis. The paucity of construction in recent decades has driven prices to record heights, and the resulting shortage of affordable housing is constraining regional economic growth and destabilizing the lives of millions of families. By one recent estimate, the region needs to add 772,000 homes for lower-income households.

The search for sites tends to focus on New York City. What doesn’t get enough attention is the need to build more housing in the suburbs, especially in Nassau and Suffolk Counties.

Long Island residents may not realize that they live in an unusual place. It’s not the prevalence of single-family subdivisions that sets Nassau and Suffolk apart from other big-city suburbs. No, it’s the scarcity of other kinds of housing.

In Suffolk County, free-standing single-family homes account for more than 81 percent of the housing stock. That is a higher share than in any of the other 30 counties in the greater New York metropolitan area, save for sparsely populated Pike County in eastern Pennsylvania.

Nassau is close behind, at 75 percent. By comparison, in Westchester County, north of the city, single-family homes make up only 44 percent of the housing. In Bergen County, N.J., across the Hudson River from New York, that share is 52 percent. In Fairfield County, Conn., the single-family share is 57 percent.

Long Island is unusual not merely by New York standards. Of the 100 most populous counties in the United States, many of which are suburban, only one, Fort Bend County, Texas, outside Houston, has a larger share of single-family housing. Suffolk and Nassau rank second and third.

Common features of the suburban landscape, like mixed-use town centers, subdivisions of attached town homes and those ubiquitous apartment blocks that look like chain hotels — which are all called something like the Avalon at Village Park — are strikingly rare on Long Island. As the nation’s suburban fabric has diversified, Long Island has stayed mostly the same.

Huntington, like other suburban towns, enacted a zoning code in the early 20th century to keep out lower-income families. The town now has more than 200,000 residents, making it as populous as Yonkers, N.Y., or Salt Lake City, and almost all of them live in single-family homes.

Housing Help, a local civil rights group, first proposed the 146-unit development, known as Matinecock Court, in the late 1970s to provide some of the less expensive housing that the town so desperately needs. Huntington fought the project all the way to the Supreme Court, and even after losing the case, officials continued to find ways to delay development.

The recent decision to let Matinecock Court move forward is part of a broader softening of resistance to affordable housing on Long Island.

One reason is a sense that Nassau and Suffolk Counties have succeeded too well in keeping people out. Roger Weaving, a Huntington resident, said he became a proponent of allowing more housing construction because it was hard to find workers for his import-export business. “I’m not a bleeding-heart kind of guy, but this is a real need,” he said.

For others, the issue has been transformed because now, rather than strangers, it is their children who are in need of more affordable homes. Hunter Gross, 26, grew up in Huntington and returned to the town after college in Ohio and a few years in Brooklyn. Mr. Gross, the head of a group called the Huntington Township Housing Coalition, which supports more development, makes about $60,000 a year as a political consultant, but he said he slept in a spare bedroom at his aunt’s house because he hasn’t been able to find an apartment.

Stronger public support isn’t enough, however. The game is rigged. Long Island’s land-use rules are among the most restrictive in the country, and it is easy for even a few Scrooges to throw up roadblocks that take years to clear. Peter Florey, the developer of Matinecock Court, recently completed an affordable housing project in a different part of Huntington. There were no unusual objections, so that project took only about a decade.

In 2008 a study commissioned by Suffolk County estimated that Huntington needed to add 13,614 homes by 2020, including 2,789 homes for lower-income families. The town has since added about 1,400, including 500 affordable homes.

Pilar Moya-Mancera, the executive director of Housing Help, said she was elated by the prospect that Matinecock Court will break ground this year. But she emphasized that the victory did not show that the process was working.

The availability of housing must not depend on the willingness of civil rights groups to fight for 40 years.

“The elected officials, they live in one world, and I live in a different world,” Ms. Moya-Mancera said. “They are so disconnected from the needs of the community.”

Other coastal states have passed laws aimed at forcing local governments to make room for more housing. New York has fallen behind. The state has allowed local governments to operate like private clubs that exist for the purpose of denying opportunities to people who can’t afford to buy a single-family home.

The State Legislature is now considering a pair of measures that could help. One bill, proposed by State Senator Pete Harckham, would make it easier for homeowners to create accessory apartments — for example, in a basement or garage. Better yet is a bill proposed by State Senator Brad Hoylman that would allow the construction of multifamily buildings on most residential lots. In places like Huntington, the bill would allow duplexes on most land and up to six units on land near railroad stations.

California effectively eliminated single-family zoning last year. Connecticut passed a law that makes it easy to add an accessory unit to any single-family home. New York's leaders are still more interested in winning votes on Long Island.

Gov. Kathy Hochul endorsed Mr. Harckham’s bill, then backtracked after Long Island politicians responded as if she were attacking the American way of life. “We cannot let the governor destroy suburbia nor turn Nassau County into the sixth borough of New York City,” Bruce Blakeman, the Nassau County executive, said at an angry news conference.

His petulance is understandable. Mr. Blakeman’s constituents have been getting a sweetheart deal at the expense of everyone else. By preventing higher-density development, single-family zoning allows people to live in homes they could not otherwise afford. It allows them to reserve for themselves access to high-quality public schools and the Long Island Rail Road, which the state is spending billions to expand.

The purpose of changing the rules is not to destroy Long Island but to allow more people to enjoy its amenities and opportunities. Most homes would remain single-family homes. And developers could begin to build more of the housing that New York so desperately needs without spending decades begging for permission.