Document Type


Publication Date



Oregon -- Population -- Statistics, Demographic surveys -- Oregon, Population forecasting -- Oregon -- Linn County


Different parts of the county experience different growth patterns. Local trends within the UGBs and the area outside them collectively influence population growth rates for the county as a whole.

Linn County’s total population has grown steadily since 2000, with an average annual growth rate of 1.2 percent between 2000 and 2010 (Figure 1). However, some of its sub-areas experienced more rapid population growth while others experienced opposite trends during the 2000s. Millersburg and Harrisburg posted the highest average annual growth rates at 7.1 and 2.6 percent, respectively, during the 2000 to 2010 period. Concurrently, the Linn portions of Gates and Idanha, along with Waterloo, were the only sub-areas to experience negative average annual growth rates at -0.5, -3.9 and -0.4 percent, respectively.

Linn County’s positive population growth in the 2000s was largely the result of substantial net in-migration. Meanwhile, an aging population not only led to an increase in deaths but also resulted in a smaller proportion of women in their childbearing years. This, along with more women choosing to have fewer children and having them at older ages has led to fewer births in recent years. The larger number of births relative to deaths caused a natural increase (more births than deaths) in every year from 2000 to 2015. While net in-migration far outweighed natural increase during the bulk of the last decade, as net in-migration has slowed, the gap between these two components has diminished in recent years—thus slowing total population growth in the county (Figure 12).

Total population in Linn County as a whole and in its sub-areas will likely grow at a slightly faster pace in the near-term (2017 to 2035) compared to the long-term (Figure 1). The tapering of growth rates is largely driven by an aging population—a demographic trend which is expected to transition into a natural decrease. As deaths outpace births, population growth will become increasingly reliant on net in-migration.

Even so, Linn County’s total population is forecast to increase by more than 22,800 over the next 18 years (2017-2035) and by more than 58,700 over the entire 50 year forecast period (2017-2067). Sub-areas that showed stronger population growth in the 2000s are generally expected to experience slower rates of population growth during the forecast period, while sub-areas that experienced negative growth rates are expected to experience very slight and steady positive growth rates. The area outside UGBs is the only sub-area that will experience a negative growth rate in the longer term.


This report is published by the Population Research Center at Portland State University, and is a product of the Oregon Population Forecast Program.

The introductory presentation, preliminary forecast presentation, and Linn County final forecast tables are attached to this document as supplemental files.

Persistent Identifier

introductory presentation.pdf (2911 kB)
Introductory presentation

Linn_prelim_presentaton.pdf (1565 kB)
Preliminary presentation

Linn_County_Final_Forecast_Tables (1).xlsx (134 kB)