Fossil, OR has a population of 403 and is the 20,839th largest city in the United States. The population density is 514 per sq mi which is 1199% higher than the Oregon average and 468% higher than the national average. The median age in Fossil is 62 which is approximately 60% higher than the Oregon average of 39. In Fossil, 73% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 57% of Fossil residents were born in Oregon, 43% were born out of state, 0% were born outside of the United States and 0% were foreign born.