Riverdale High School is a public high school in the Dunthorpe neighborhood of Portland, Oregon, United States. The high school is unique in that it is a public school, but students from outside the district must go through an admissions process and pay tuition to attend, unless they get a district transfer from their original district. According to analysis of U.S. Census data from 2006 through 2010, the Riverdale School District is the third richest school district in the United States.