Oregon nearly always experiences population increases from both sources. From 2008 to 2009, the state's total population increased by about 42,670, according to Census estimates. Natural increase added about two-fifths of these people, and net in-migration added the other three-fifths.
Migrants to a state come from other states and other countries. Some states - Oregon included - gain population from both sources. About one-third of Oregon's net in-migration is from other countries; the rest comes from elsewhere in the U.S. Washington, our neighbor to the north, also adds population from both domestic and international sources, but their international migrants make up nearly half of their net in-migration.
Oregon's southern neighbor, California, is a bit different. The Golden State is constantly losing domestic residents; it needs a large influx of international migrants in order to have net in-migration. During the last decade, California has seen years of positive and years of negative net migration. The pattern of population change in California is unique among states in the Western U.S.
Within Oregon, 21 counties experienced a population increase and 15 experienced a decrease from 2008 to 2009. The 15 counties losing population changed in different ways: five saw both a natural decrease and net out-migration; four saw a natural decrease offset net in-migration; and six saw a natural increase outweighed by net out-migration.
Interesting growth patterns occurred in a few counties, including Baker, Lincoln, and Wallowa. These three areas gained population because net in-migration overcame a natural decrease. Deschutes also experienced a unique growth pattern: Its net out-migration was overcome by a large increase in the natural population.
Overall, Oregon's counties show diverse population trends. Some are always gaining, others are often in decline, and a few bounce both directions. One thing is certain: In the long run, the state's total population keeps increasing.