Well...
According to the above 2009 Pew survey (N=2,884) from Pew, the acceptance of interracial marriage is lower in the Southern US states. Note however, that the difference between regions is so low that one can only conclude that the West is more accepting than the other 3 regions, not that the South is less accepting. As demonstrated above, more pronounced differences can be found in other categorical divisions, especially between age groups.
A more recent 2011 survey (N=2,003) provides a greater difference with a different wording (Change for better/worse), but here the Midwest comes out as the least acceptive US region when it comes to interracial marriage. Note, however, that none of the categories yield a percentage of 20 percent or more who find increased frequency of interracial marriage a change for the worse.
And finally, there is a steady increasing trend in the US towards greater acceptance of interracial marriage, so I guess the subject is somewhat... meh.
Source: http://www.pewsocialtrends.org/2012/02/ ... ermarriage
Methodology: http://www.pewsocialtrends.org/2012/02/ ... ethodology