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New population forecasts by Portland State University indicate Multnomah County will lose 17,474 children between the ages of 5 and 18 in the next decade.
In 2025, PSU estimates 106,893 school-aged children resided within the county. Declining birth rates and a net out-migration of children over the past decade are expected to soon start affecting the county’s teenage population. By 2036, in a medium-growth scenario, PSU’s Population Research Center forecasts there will be 89,419. (U.S. census data shows Multnomah County had 795,391 residents in 2025.)
At the same time, the forecast anticipates the county’s senior population (65 and older) will increase by 21,538 over the next decade. The Oregon Journalism Project has previously reported on some of the consequences of an aging population, including dwindling social services for younger people and difficulties for local economies as older people spend less.
Dr. Ethan Sharygin, director of the Population Research Center, tells WW that “the pandemic didn’t affect the trajectory of birth rates much—they’ve been in long run secular decline.” Instead, the loss of school-aged children comes as the effect of a “complete reversal of migration trends in response to the way that the city changed in the years afterward.”
The projections come as part of a forecast Multnomah County commissioned as it tries to understand how many seats it will need to deem its subsidized preschool program universal. As WW has previously reported, data from the PSU forecast indicates the county will need just over 8,000 seats to give one to every 3- and 4-year-old whose family might want one.
A previous population estimate that the county had relied on, conducted before the COVID-19 pandemic, had led officials to believe they would need closer to 11,000 seats to reach universality, a goal they had hoped to hit by 2030. On Tuesday, Preschool for All director Danisa McLean said the findings were a sign that the program was on track to meet its goal early. The program this year has confirmed about 7,100 seats.
Demographic forecasts have also had a significant impact on Preschool for All’s financial sustainability, given that seat costs take up the bulk of the program’s budget. The county’s financial modeling indicates the program has a robust fund balance that can weather increased seat costs and delays to a scheduled tax increase.
The Population Research Center’s medium-growth scenario assumes a small increase in total fertility rates and an increase in net migration to 3,500 by 2030, matching average migration in the county during 2010 to 2020.
In recent years, Multnomah County’s net migration has suffered from domestic out-migration—a fancy way of saying people are leaving town for other places. Census data shows a total net out-migration of 22,416 over the past five years. In recent years, international migration into the county has helped soften the domestic out-migration blow. In 2025, the county gained 619 residents from net migration.
Sharygin says he’d consider the net migration assumption a neutral, safe one. “It’s high enough that the county won’t be caught unprepared if there’s slightly higher demand than expected,” he says, “but also shouldn’t be extremely overresourced if recovery takes longer or if the situation declines from the current trajectory.”
The numbers from the latest forecast reflect concerns by officials in local school districts across Multnomah County. Declining enrollment at districts, including Oregon’s largest, Portland Public Schools, has contributed to multimillion-dollar budget deficits. PPS officials have said they expect enrollment to continue to decline for at least the next decade, and enrollment loss is working its way through the school system. (It should be noted that declining enrollment is a nationwide problem.)
PPS has engaged in enrollment rebalancing efforts at the high school level to try and even out its enrollment across buildings. As WW has reported, population projections indicate the district has overbuilt its high school capacity (“Too Many High Schools,” March 19, 2025).
One bright spot in the forecast: Under the medium-growth scenario, the county’s infant and toddler populations are forecasted to grow slightly after dipping to their lowest numbers around 2031.
Still, Sharygin says the county will have to brace for the reality of a growing number of older residents.
“It’s a bit tongue in cheek, but one might have advised PPS to develop its new school buildings for adaptive use so that they could transition into senior living apartments if the demand for elementary schools evaporates,” he says.
