When was the last time you took a trip to Chinatown? You might want to head there soon, because they might not be around for much longer. According to the Asian American Legal Defense and Education fund, Chinatowns all over the United States are being squeezed into smaller and smaller areas due to gentrification. At Wired‘s Map Labs blog, Greg Miller breaks down this break-down. Based on the maps, Boston has it the worst:

According to Census records, the percentage of the population that claims Asian heritage in Boston’s Chinatown dropped from 70 percent in 1990 to 46 percent in 2010. New York and Philadelphia’s Chinatowns did not see big change either way by that measure during the same time period, but in all three cities the proportion of homes inhabited by families and the proportion of children in the population dropped considerably. To Li that suggests that multigenerational immigrant homes are breaking up — or moving out.

To figure out the composition of these Chinatowns, volunteers went out and surveyed what types of restaurants, businesses and residential properties were in the area. Restaurants in particular are good barometers for a neighborhood’s service to immigrants. In other words, more Asian restaurants means a more robust Chinatown. But as the survey found, other restaurants and shops are moving in quickly.

The very existence of Chinatowns are a product of discrimination—immigrants created these communities to live in because they were excluded from pre-existing ones. And that tradition continues today, according to Bethany Li, author of the report. But with pressure from condominiums and high-end shops from all sides, many Chinatowns are slowly shrinking. While communities are fighting back, Li’s report says that without help they’ll be pushed out again:

Without the fights against unfettered development led by members from groups like the Chinese Progressive Association in Boston, Chinese Staff & Workers’ Association in New York, and Asian Americans United in Philadelphia, these Chinatowns would likely contain even more high-end and institutional expansion. City governments removed and replaced working-class immigrant residential and commercial land uses in each of these Chinatowns.

Bonnie Tsui at Atlantic Cities breaks down what some of those actions might be:

What’s to be done? Recommendations include allocating public land and funds for low-income housing development and retention at a more reasonable proportion to current high-end development; supporting small, local businesses to offset rising rents, given the symbiotic relationship with residents; prioritizing public green spaces; and engaging community organizations, residents, and the larger satellite communities to maintain Chinatowns as shared cultural history and home to working-class immigrants.

For many, Chinatowns are an attraction to a city, and many cities boast about their robust cultural neighborhoods. But they might not be around for much longer.

More from Smithsonian.com:

The Many Chinatowns of North America

San Francisco’s Chinatown at night