Springfield is a city in Lane County, Oregon, United States. Located in the Southern Willamette Valley, it is within the Eugene-Springfield Metro…Springfield is a city in Lane County, Oregon, United States. Located in the Southern Willamette Valley, it is within the Eugene-Springfield Metropolitan Statistical Area. Separated from Eugene to the west, mainly by Interstate 5, Springfield is the second-most populous city in the metropolitan area after Eugene. As of the 2020 census, the city has a total population of 61,851, making it the ninth-most populous city in Oregon.