Warning sign for Democrats: While overall turnout was up 12% from the 2014 gubernatorial primary, the increase was concentrated in only 9 counties, with the counties around the D.C. metropolitan area making up almost all of it. 15 counties saw declines in turnout, including every county on the Eastern Shore. It's similar to what we saw in Virginia with Northam's win heavily on the backs of metropolitan areas. The party's infrastructure in non-metropolitan areas continues to atrophy.
Democrats are becoming more and more the party of the cities. Future elections, at all levels, will see Democratic-dominated urban and suburban areas up against vast swathes of rural Republican territory. This makes maps far less interesting than in the past.