New U.S. Census Bureau population estimates show Valley County has experienced a slight population decline from migration in recent years, while several counties elsewhere in Montana continue to see significant gains.
The estimates, covering July 2022 through July 2025, show Valley County declined point-six percent due to migration, meaning slightly more people moved out of the county than moved in.
Other parts of northeast Montana saw larger losses. Roosevelt County declined 3.2 percent, Daniels and Blaine counties each fell 1.5 percent, and McCone County was down point-nine percent.
There were some gains in the region. Phillips County increased point-six percent, while Sheridan and Richland counties each grew one percent due to migration.
The contrast is significant when compared with some of Montana’s fastest-growing counties. Madison County grew 9.2 percent from migration, Broadwater County 8.9 percent, Musselshell County 7.6 percent, Sanders County six percent, and Granite and Deer Lodge counties each grew 5.8 percent.
And new Census data also provides a look at where people moving to Montana are coming from.
California accounted for 13.5 percent of Montana’s incoming domestic migrants, the largest share shown in the data. Washington accounted for 10 percent, Colorado 8.3 percent, Arizona 6.4 percent and Texas 5.9 percent.
The numbers illustrate two different migration trends playing out in Montana: substantial population gains from migration in several western and central Montana counties, while Valley County and a number of counties across the Hi-Line and northeast Montana have experienced little growth or population losses from migration.
The county figures measure population change specifically from people moving in and out and do not include the effects of births and deaths.
The Census estimates cover the three-year period ending July 1st, 2025.
Source: United States Census Bureau