‘These shifts were largely due to lower levels of net international migration, which declined nationwide.’
What happens with a secure border?
A new report from the U.S. Census Bureau describes a remarkable set of changes happening in the United States. Population growth is slowing or reversing toward decline in many metropolitan areas, and population losses are accelerating in some counties that were already shrinking.
Several things are happening behind those changes, but here’s what the Census Bureau identifies as the biggest cause:
“These shifts were largely due to lower levels of net international migration (NIM), which declined nationwide. Nine out of 10 U.S. counties experienced lower NIM levels between July 1, 2024, and June 30, 2025, compared to the year prior. The one in 10 counties that did not see a drop in international migration did not see an increase either.”
So far fewer people are coming to the United States, which is slowing population growth in the places those immigrants were most likely to go. But we’re not just discussing immigrants, because we’re largely talking about a more specific type of immigration.
In a report last summer, the Federal Reserve Bank of San Francisco identified the leading cause of the increasingly apparent decline in net migration: “Fewer undocumented immigrants arriving at or between ports of entry also led to a significantly lower 2025 NIM projection relative to 2023 and 2024…[as] the inflow of undocumented immigrants declined from a peak of around 1.0 million in the fourth quarter of 2023 to around 180,000 in the second quarter of 2025.”