Here's a map I made based upon Voter Registration in the 2012 election that has been listed publicly by states as of 11/1/2012. Not all states do this, and the colors represent the majority of citizens registered for a specific party. I thought I'd share the map.
Red = Majority of Republicans registered for this county
Blue = Majority of Democrats registered for this county
Gray = Majority of Independents/Unaffiliated/No Affiliation registered for this county
White = No Information was Provided
Interesting fact discovered:
All the Deep South states (except FL) divide up their Voter Registration statistics by Race/Sex/Age with no mention of Party.
Texas doesn't believe in Voter Registration Statistics to be shared on its website at all, neither does Hawaii
Alaska has voter registration statistics but divides it up not by county but by districts.
The rest of the Whited out states provide total number of voters registered by county and no further breakdown.