For many of us it is easy to forget the eras prior to MLS. But the soccer history we have here in Cascadia is part of why this Cascadia Cup thing is special and will remain special. It is why the Supporters Groups are fighting to maintain the trademark.
It is also full of success for the Seattle Sounders. How much success depends on how you count the numbers. For the front office of Seattle they include even contests that do not include a league that existed between the NASL and the A-League and provide the following records of the contest;
All-Time Series Record
Year League Record
1975-82 NASL Sounders 13 wins; Timbers 8 wins
1985-90 WSL FC Seattle 5 wins; FC Portland/Timbers 6 wins; 2 draws
2001-08 USL-1 Sounders 20 wins; Timbers 13 wins; 5 draws
2009-10 U.S. Open Cup Sounders FC 1 win; Timbers 0 wins; 1 draw
2011-12 MLS Sounders FC 2 wins; Timbers 1 win; 2 draws
Totals: 79 matches played; Seattle 41 wins; Portland 28 wins; 10 draws
Now there is evidence that there was another FC Seattle win just prior to the WSL era when the two teams played, but did not play in a recognized league.
There are of course other ways to count the history, and Likkit provides a fact sheet for the NASL-ALeague/USL-MLS eras of the three cities' soccer clubs.