The Atlantic has an article about the geographic distribution of partisan prejudice in the United States. There are three maps - overall, by Democrats, and by Republicans. The interactive maps in the article allow for mouseover data about individual counties. Not vouching for the statistical model and definitions of prejudice chosen by the authors, of course … but it is quite interesting.

https://www.theatlantic.com/politics/archive/2019/03/us-counties-vary-their-degree-partisan-prejudice/583072/

The Geography of Partisan Prejudice: A guide to the most—and least—politically open-minded counties in America