Pew Research Center has a new survey out on that (n=1983 adults). It has been written up in various ways, but the major result people talk about is the finding that those who believe humans were created exactly as they are now are more likely to be Republicans now than in 2009:
There also are sizable differences by party affiliation in beliefs about evolution, and the gap between Republicans and Democrats has grown. In 2009, 54% of Republicans and 64% of Democrats said humans have evolved over time, a difference of 10 percentage points. Today, 43% of Republicans and 67% of Democrats say humans have evolved, a 24-point gap.The researchers looked at a lot of stuff to account for the change, but couldn't completely do that:
Differences in the racial and ethnic composition of Democrats and Republicans or differences in their levels of religious commitment do not wholly explain partisan differences in beliefs about evolution. Indeed, the partisan differences remain even when taking these other characteristics into account.
That's weird. My first guess for an explanation would have been that Republican Party is now more religious than it was in 2009, in the sense of having more fundamentalists in it. Perhaps "differences in their levels of religious commitment" doesn't account for that aspect? On the other hand, the change from 2009 could be just getting a non-representative sample by accident, either that year or now.