Rainier, OR has a population of 1,971 and is the 11,103rd largest city in the United States. The population density is 483 per sq mi which is 1120% higher than the Oregon average and 433% higher than the national average. The median age in Rainier is 37 which is approximately 6% lower than the Oregon average of 39. In Rainier, 48% of the population over 15 years of age are married, 93% speak English and 3% speak Spanish. 33% of Rainier residents were born in Oregon, 62% were born out of state, 0% were born outside of the United States and 5% were foreign born.