A positive value of net migration means more people moving into an area than leaving it, while a negative value of net migration indicates more people leaving an area than moving in. An area naturally increases in population if more births than deaths occur in a given year.
From 2010 to 2015, Oregon’s net migration gain was 120,000, which made up about 65 percent of the population gain. The net migration gain in metro areas of the state was 105,100, which accounted for 88 percent of total net migration gains in the state. Since 83 percent of Oregonians live in a metro area, this gain suggests the share of Oregonians living in metro areas is increasing slightly.
To learn more about the counties experiencing population declines, read Employment Economist Felicia Bechtoldt's article "Oregon’s 2015 In-Migration Was the Highest Since 2006".