Harrisburg, OR has a population of 3,687 and is the 7,806th largest city in the United States. The population density is 2,651 per sq mi which is 6595% higher than the Oregon average and 2826% higher than the national average. The median age in Harrisburg is 33 which is approximately 16% lower than the Oregon average of 39. In Harrisburg, 63% of the population over 15 years of age are married, 83% speak English and 15% speak Spanish. 59% of Harrisburg residents were born in Oregon, 29% were born out of state, 2% were born outside of the United States and 11% were foreign born.