A leading affordable housing nonprofit in Arlington County is expanding its operations into Montgomery County, another sign of a growing regional focus on preserving or producing homes that lower-earning residents can afford.

The Arlington Partnership for Affordable Housing purchased Snowden’s Ridge, an 87-unit townhouse complex in Silver Spring, months after Montgomery’s largest housing nonprofit, the Montgomery Housing Partnership, acquired its first-ever property in Washington.

Snowden’s Ridge was one of the last privately owned complexes in Montgomery with a rent subsidy contract under the federal Section 8 program.

Earlier this year, owners were considering selling the complex; if private developers had acquired it, they may not have chosen to renew the federal contract. The Arlington partnership says it will commit to renewing the contract and ensure that rents stay stable in the property, where 82 percent of units serve households that make less than 30 percent of Montgomery’s area median income — about $36,000.

“It’s great news,” said Montgomery County Council member Hans Riemer (D-At Large), who chairs the council’s housing committee. “We need all hands on deck here. . . . The more competition in the sector, the better.”

Housing experts say the partnership’s decision to expand across the Potomac River is both a symptom and a response to a growing list of issues affecting the entire Washington region, pushing local actors to work beyond their jurisdiction.

“We’re at this inflection point with affordable housing where we have all these different forces together, putting pressure on the region,” said Montgomery Housing Partnership President Rob Goldman.

He cited escalating rates of gentrification in the District, Amazon’s decision to locate a second headquarters in Arlington, and the construction of the Purple Line light rail connecting Montgomery and Prince George’s counties.

“Organizations are looking regionally because these are regional problems with regional implications,” said Gustavo Velasquez, director of the Urban Institute’s Washington-Area Research Initiative, which released a report last month declaring that the region needs to collectively add 374,000 housing units by 2030.

The report said Montgomery — Maryland’s largest jurisdiction, with a population of about 1 million — needs to add 23,100 low-cost housing units, the most of any individual county or city.

In recent years, nonprofits that have traditionally operated within a single county or city have identified new opportunities in neighboring jurisdictions — not just in terms of need but also in terms of resources, Velasquez said.

When the Arlington partnership decided in 2018 to look for outside projects, it did so for two main reasons, said chief executive Nina Janopaul: The organization had the capacity to expand beyond the Virginia county of 230,000, and it was becoming increasingly clear that there was an equal, if not more dire, need for affordable housing elsewhere.

“The problem is big in Arlington, but it’s even bigger in Fairfax and in Montgomery,” Janopaul said.

In the 2019 fiscal year, Montgomery invested a record $107.3 million in affordable housing through its Housing Initiative Fund — nearly eight times more than Arlington’s fund of about $14 million.

“In Arlington, there’s simply a finite number of projects they could fund every year,” Janopaul said. “We have a strong and robust staff, we have some capital reserves. . . . To some degree, we have to be opportunistic.”

The Arlington partnership purchased Snowden’s Ridge for $18.5 million, $2.75 million of which was a loan from Montgomery’s Housing Initiative Fund.

“We’re very excited about this specific project,” said Stephanie Killian, who leads the county’s housing division. “The Section 8 vouchers attached to the unit — they’re very precious.”

Goldman, who runs the Montgomery housing partnership, said the organization’s acquisition of a property in Southeast Washington this year is part of a“growth model” that could also allow them to expand existing operations in Montgomery.

Velasquez, however, noted that the growth of housing nonprofits is still significantly limited by the extent of government funding available.

He said elected officials in Montgomery, Arlington and elsewhere should follow D.C. Mayor Muriel E. Bowser (D) in setting clear numerical targets — and therefore solid commitment, Velasquez says — for affordable housing units.

Bowser has pledged to add 12,000 affordable housing units by 2025, and on Tuesday, she unveiled specific goals for where to locate them.

“Ultimately, these organizations rely on dollars,” Velasquez said. “And right now, no question — D.C. is ahead.”