Rivalries
The Seattle–Portland and Seattle–Vancouver rivalries formed in the years that the NASL-Sounders and USL-Sounders were playing in Seattle. In 2004, the fan-based Cascadia Cup was created to formalize the competition between the Seattle, Portland, and Vancouver USL teams. This geographic rivalry was renewed when the MLS expansion teams in Portland and Vancouver began play in the 2011 season.
The fan-created Heritage Cup competition with the San Jose Earthquakes began in the 2009 MLS season. MLS teams that carry on the names of their NASL predecessors are eligible to compete. The results of their league matches determine the winner.
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