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 24/7 Wall St.'s analysis of U.S. Census data from 2006 through 2010, the Riverdale School District is the third richest school district in the United States.