These folks have created a map where the most and least racist, homophobic and disability related tweets originate from
Looking at it on a countrywide scale it's pretty depressing, but when you zoom into state or county level, it actually becomes a much better picture.
Seems that the vast majority of people tweeting hate speech are very localized, and much of the country has grown up.
The map is interactive, so you can look right down to your own county.
From the site
"The prominence of debates around online bullying and the censorship of hate speech prompted us to examine how social media has become an important conduit for hate speech, and how particular terminology used to degrade a given minority group is expressed geographically. As we’ve documented in a variety of cases, the virtual spaces of social media are intensely tied to particular socio-spatial contexts in the offline world, and as this work shows, the geography of online hate speech is no different.
Rather than focusing just on hate directed towards a single individual at a single point in time, we wanted to analyze a broader swath of discriminatory speech in social media, including the usage of racist, homophobic and ableist slurs."
Take a look and see where your state or county stands.