Reddit is an interesting corner of the internet. The college football section (/r/CFB) is consistently filled with awesome stuff, and is often the source of whatever college football related jokes and memes hit your social media timeline of choice.
This off-season two users (cinciforthewin and bakonydraco) took a survey, resulting in 3462 votes for 156 teams, and used respondent location to map out each fan base geographically. That's not a huge response (3 percent of their users), and you can see the raw data here. A lot of the lesser populated counties only had one vote, or maybe a small handful of votes, so small sampling bias is definitely an issue they tried to account for. You can see their whole post, including the methodology here.
Here's the Fan Map their data generated.
There's some weird quirks in that, which are probably due to the small response rate of their survey.
Here's what it looks like when they broke it out into heat maps for individual teams.
Wazzu owns most of the geographic area in the State, while UW is pretty isolated to the I-5 corridor. This seems reasonable. The Cougs also get some love from around Omaha and Lincoln, Nebraska; Monroe, Louisiana; Columbus, Ohio; East Lancing, Michigan; Los Angeles, California; and Phoenix, Arizona. Which I guess would make sense for transplants, and people that held on to feelings after rooting for WSU against Michigan in the 1998 Rose Bowl. For Nebraska and Louisiana, I got nothing.
Noticeably absent -- Texas.
Northern Louisiana represent!*
*Or the one lone Coug survey respondent holding it down in Ouachita Parish