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


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

Columbia County’s total population has grown modestly since 2000, with an average annual growth rate of above one percent between 2000 and 2010 (Figure 1). However, some of its sub-areas experienced more rapid population growth during the 2000s. The most populous UGB, St. Helens, along with the second most populous, Scappoose, posted the highest average annual growth rates at 2.3 and 2.8 percent, respectively, during the 2000 to 2010 period.

Columbia County’s positive population growth in the 2000s was largely the result of substantial net in-migration paired with modest natural increase. An aging population 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 led births to stagnate in the last decade. Despite this trend, the large number of births relative to deaths caused a natural increase (more births than deaths) in all years from 2000 to 2015, except 2012. While net in-migration outweighed declining natural increase during the early and middle years of the last decade, the gap between these two numbers shrank during the later years—slowing population growth considerably. In more recent years (2013 to 2015) population growth has rebounded slightly, primarily through net in-migration (Figure 12).

Total population in Columbia County as a whole and 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 contribute to natural decrease (more deaths than births). As natural decrease occurs, population growth will become increasingly reliant on net in-migration.

Even so, Columbia County’s total population is forecast to increase by nearly 9,000 over the next 18 years (2017-2035) and by more than 17,000 over the entire 50 year forecast period (2017-2067). Sub-areas that showed strong population growth in the 2000s are expected to experience slower rates of population growth during the forecast period due to potential land constraints and an aging population.


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 Columbia County final forecast tables are attached to this document as supplemental files.

Persistent Identifier

Columbia intoductory presentation.pdf (2664 kB)
Introductory presentation

Columbia_prelim_presentation.pdf (1522 kB)
Preliminary presentation

Columbia_County_Final_Forecast_Tables.xlsx (133 kB)