Monroe is a city in Benton County, Oregon, United States. The population was 607 at the 2000 census. It is part of the "Corvallis, Oregon Metropolitan Statistical Area". Monroe is located midway between Eugene and Corvallis and the city experiences a strong friendly rivalry between fans of the Oregon Ducks and the Oregon State Beavers.
According to the United States Census Bureau, the city has a total area of 0.5 square miles (1.2 km²), all of it land.
As of the census of 2000, there were 607 people, 225 households, and 166 families residing in the city. The population density was 1,274.9 people per square mile (488.3/km²). There were 262 housing units at an average density of 550.3 per square mile (210.7/km²). The racial makeup of the city was 96.71% White, 0.33% African American, 0.99% Native American, 0.33% Asian, 0.33% Pacific Islander, and 1.32% from two or more races. Hispanic or Latino of any race were 10.05% of the population.