Montana’s Eight Most Populous Counties See Sharp Rise in Older Residents Over Children

Montana’s largest counties saw a notable rise in older residents relative to children from 2020 to 2025.

The Montana Free Press analysis, based on an aging index reported by the Legislative Fiscal Division, reveals a structural demographic shift. This trend signals a growing share of adults age 65 and older compared to residents under 18 across the state’s eight most populous counties.

The aging index, which measures the number of residents 65 and older per 100 children, increased statewide from 93 in 2020 to 110 in 2025. Montana added over 36,000 residents aged 65+, even as the number of children declined by about 2,500. Missoula County experienced the largest change, with its aging index rising from 91 to 112, adding nearly 3,500 older residents alongside a decline of more than 1,100 children. Other counties such as Flathead and Ravalli also grew older populations, though Ravalli remains the oldest large county by aging index.

While no future projections or policy responses have been detailed, this demographic pattern warrants attention for its potential economic and social impacts.

Montana’s demographic changes could influence local labor markets, healthcare demand, and housing needs, especially given the state’s rural character and distance between population centers. Businesses and policymakers might consider how an older population affects economic dynamics and community services in these counties.

Montana’s most populous counties have grown older, census data shows
By Jacob Olness, Montana Free Press