Monroe is a city in Benton County, Oregon, United States.

According to the United States Census Bureau, the city has a total area of 0.51 square miles (1.32 km2), all of it land.

[6] The city was formed around a small sawmill established by Joseph White in 1852.

Around the same time, Roland Hinton formed the town of Starr Point north of White's Mill.

In 1857, Starr Point combined with White's Mill to form the town of Monroe.

Since the construction of the Interstate 5 highway in the 1960s, the city has turned into a rural farming community.

It is the site of the historic Hull-Oakes Lumber Mill, the only steam-powered sawmill operating in the U.S.[8] At the 2010 census, there were 617 people, 251 households and 165 families residing in the city.

25.1% of all households were made up of individuals, and 8% had someone living alone who was 65 years of age or older.