There is an eerie similarity between the patterns of support of the two parties' nominees. Both Trump and Clinton got their bedrock support from their parties' most downscale (and in general elections most faithful) constituencies.
Blacks, especially Southern blacks, produced just about all of Clinton's popular vote margin over Bernie Sanders. Non-college-educated whites produced the highest percentages for Trump. "I love the poorly educated!" he exclaimed after winning in low-education Nevada.
It also appears that Trump and Clinton ran worst among groups with high degrees of what scholars Robert Putnam and Charles Murray call social connectedness or social capital. Trump was especially weak among socially connected Mormons and German-Americans and strong in areas with high opioid addiction. Both were weaker in caucuses, which favor the socially connected, than primaries.