Oregon's voter system is unique: in 2015 the state implemented automatic voter registration, by which newly licensed drivers are automatically registered to vote. The system has been credited with enrolling more than 67,000 voters.
But because Oregon has closed primaries, those voters needed to have registered as Democrats to participate in the Tuesday's primary, giving Clinton a built-in advantage.
Both Sanders and Clinton campaigned in some capacity in Oregon, with former President Bill Clinton stumping for his wife and Sanders making several campaign stops in the state as early as January with massive rally attendance.
This post has been updated.