Oakdale is a city in Washington County, Minnesota, United States, is a suburb of Saint Paul and is on the eastern side of the Twin Cities Metropolitan area. The population was 27,378 at the 2010 census. Oakdale is the 32nd largest city in Minnesota, in terms of population. Oakdale lies entirely within the North St. Paul–Maplewood–Oakdale school district, but the city's students are split into two high schools.