Even in enemy territory, the 12th Man could be heard on this the biggest Blue Friday of the year. They rallied in bars across Northern California and refused to be quiet, even when heckled by 49ers fans.
The Silicon Valley Seattle Seahawks group was started about two years ago in Mountain View, California.
It's a city that sits about 40 miles south of San Francisco, and just a few miles from the 49ers new stadium. Still, that didn't stop Seahawks fans from making plenty of noise there.
About three dozen 12s gathered at Saint Stephen's Green Pub, decked out in blue and green. They ate dinner together, they shared Seahawks stories, and spent much of Friday evening cheering and gearing up for Sunday's NFC Championship.
Organizers say the bar owners agreed to let Seahawks fans start watching games there about two years ago, and the group has been growing ever since.
The president of the Northern California Seahawkers Club tells KING 5 there are events planned at about seven bars throughout the area on Sunday, so that the 12th Man in 49ers country has a place to watch the game.