A woman and man sit on a bench along the Presumpscot River in Westbrook on Tuesday Sept. 21. 2021. The city abuts Portland to the west, with their downtowns lying about 7 miles apart. Westbrook is partially framed by Interstate 95 and routes 302 and 22. Credit: Troy R. Bennett / BDN

The city of Portland’s population continues to stagnate even as its suburbs grow rapidly, a data analysis by the Bangor Daily News shows.

Of the 34 communities in the Portland metro for which the U.S. Census Bureau recently released population numbers for 2021, the city of Portland ranked dead-last in growth since 2020, losing 100 residents.

But in Greater Portland — known as the Portland metro — suburbs have been growing substantially with hundreds of thousands of new residents in recent years, something that’s exacerbated by the increasing unavailability and unaffordability of housing in the city itself.

Though there are communities more expensive than the city of Portland, including Kennebunkport, Cape Elizabeth and Falmouth, the vast majority of towns and cities in the Portland metro area are cheaper, according to Zillow data from May.

Many of those communities are seeing much of the new in-migration, including Westbrook (where the typical home is $94,000 cheaper than in Portland), Biddeford ($72,000 less), Gorham ($56,000 less) Saco, ($46,000 less) Brunswick ($43,000 less), South Portland ($31,000 less) and Wells ($28,000 less).

“As the cost of housing has grown significantly in Portland, Westbrook has been an affordable alternative to housing in the area,” said Westbrook Mayor Michael Foley.

New residents include both people moving from other parts of Maine and people from out-of-state looking to settle in the Portland area, he said.

They have been helped in their housing search by the development of many new housing units in Westbrook, almost 2,000 units from 2001 to 2021, according to Foley.

While the ratio of Portland residents to non-Portland residents in the metro has been shrinking for almost a century, today it is at the lowest it has been since the beginning of modern county boundaries around 1860 when James Buchanan was president. Only 12 percent of people living in the Portland metro live in the city itself today.

That means that even if people likely have a multitude of economic, social or familial connections to Portland, almost nine out of 10 residents in the area don’t live in Portland itself.

The places seeing the most new residents include South Portland (500 new residents), Scarborough (430), Saco (290) and Eliot (240).

Eliot actually saw the highest growth percentage-wise from 2020 to 2021 by far, according to Census Bureau numbers, with its population increasing by 4 percent.

Like many of Portland’s other southern suburbs, it has the added allure of being close to both the regional giant of Boston and Maine’s largest city.

Prior to that, Ogunquit saw the largest population growth of any Portland metro community of over 100 people from 2010 to 2020. The influx of people was partially attributable to its access to both Portland (38 miles) and Boston (77 miles), according to select board chair Heath Ouellette.

Portland’s status also makes it regionally unique: among the largest metro areas in each of the six New England states, most have a far higher rate of residents living in the base city itself.

Even Boston, which has become known for its densely populated suburbs, has 14 percent of its residents living in the city itself. And 27 percent of residents in the Manchester metro — the second largest metro in northern New England to Portland — live in the city.

As suburbs take advantage of the desire by many to live just outside of Portland, it remains to be seen whether Portland will continue to spread out.

Foley expects that Westbrook will see another 1,000 to 2,000 housing units in the years ahead as it continues to grow. It’s a more optimistic than ever prospect for the community amid a housing shortage, he said.

“It hasn’t been too overwhelming — an average of 100 units per year,” Foley said, referring to growth in recent years. “The community’s really been able to digest it.”