Migration and Montana's changing demographics.

• Author: Young, Douglas J.

Migration had dramatic impacts on Montana during the past two decades, affecting the total population, its distribution between rural and urban areas, and composition by age, including school-age populations. Montana as a whole saw more people move in than out, except among those in their twenties who continue to leave the state. In fact, net migration accounted for just over one-half of Montana's total population gain of 87,000 during the decade. The rest of the gain came from natural increase: births minus deaths.

Migration patterns differed dramatically by region of the state. The western and southern parts of the state experienced inflows of most age groups, including 18- to 22-year-olds attending the two largest universities. But like the rest of the state, 26- to 31-year-olds generally left in larger numbers than they arrived. In contrast, the eastern and northern regions of Montana experienced very little in-migration of any age group. Yellowstone County--the largest metropolitan area in the state--had the most robust pattern of in-migration by all age groups except 18- to 20-year-olds.

This report uses population data from the 2000 and 2010 Censuses and death data from the Centers for Disease Control and Prevention (CDC) to estimate net migration to Montana. Net migration may be positive or negative, i.e. more people may move in than move out, or vice versa.

Figure 1 (page 13) displays net migration to Montana during the decade 2000 to 2010. Migrants are classified by their age in 2010. Two features are noticeable. First, overall net migration was positive: 46,000 more people moved into Montana than moved out during the 2000s. Second, migration varied dramatically by age. A significant number of young people left the state during the 2000s. Specifically, about 8,700 more people ages 22 to 31 left the state than moved in, amounting to about 8 percent of this group's population in 2000. Net migration was positive for every other age group. Writing in the Montana Business Quarterly in 1997, Christiane Von Reichert and James Sylvester noted that about 60 percent of the people moving to Montana have some sort of tie to the state--either they lived here previously or have relatives in the state. Apparently, they brought their children with them as well--migration increased the number of 10- to 17-year-olds by almost 10,000 during the decade.

Dramatic differences in migration occurred across regions. Figure 2 shows that about 60,000 more...