A coalition of elected officials, community activists, and labor and civic leaders in New York City is already stirring ahead of the next census in 2030 amid a brewing battle over whether to include noncitizens in the population count.

These allies came together for the last census, in 2020, running phone banks and flooding social media, to reach more New Yorkers at the height of the coronavirus pandemic.

Now they are beginning to mobilize again — this time over what they see as threats from the Trump administration and the Republican-led Congress to exclude noncitizens, which could lead to a significant undercount of the city’s population.

“I have to say it feels like I’m at a census reunion,” said Councilwoman Julie Menin, a Democrat from Manhattan’s East Side, as she welcomed about 150 people at an April gathering at New York Law School in Lower Manhattan.

Though the population of New York State reached 20.2 million in 2020 — buoyed by the growth of its largest city to a record 8.8 million — it has steadily lost ground for decades to faster-growing states, like Florida and Texas, in the southern and western parts of the United States.

One result of that is the state’s shrinking congressional delegation, which has dropped to 26 representatives from 45 in the 1940s.