The MAX has five lines, all of which run through downtown Portland (also known as city center).
Blue Line covers Hillsboro/City Center/Gresham; Green Line covers Clackamas/City Center; Red Line covers Airport/City Center/Beaverton; Yellow Line covers Expo Center/City Center; Orange Line  covers Milwaukie/City Center. For a more detailed list of stops, visit the Max light rail section of the TriMet website.