Duval County (almost entirely Jacksonville) is one of the most conservative urban counties in America. It is usually about R+2 or so. It barely went for Obama.
This is incorrect. Obama lost Duval County to Mitt Romney by about three percentage points in 2012. He lost it to John McCain by a narrower two percentage point margin in 2008. However, it is possible that Obama may have won the city of Jacksonville in either of those years, since Duval County does contain some areas that are outside of the city limits. Hillary Clinton carried the city itself by a narrow margin, while losing the county as a whole to Trump in 2016 by slightly over a percentage point.
