Maryland has closed primaries, which means that only registered members of a party can vote in its primary. Partisan leanings vary tremendously around the state, so the share of a county’s primary voters often differs quite a bit from its population share.

The above table shows the share of all statewide Democratic primary voters in the 2018 Democratic primary as well as eligible voters (i.e. registered Democrats) at that time and now. Together, Prince George’s and Montgomery made up two-fifths of Democratic primary voters in 2018. Despite being considerably smaller in population than Montgomery, Prince George’s has the same share of voters because it leans even more heavily Democratic than Montgomery.

However, if turnout patterns remain the same, Montgomery looks to ease past Prince George’s next year as the gap in eligible voters has closed by 0.5 points and Montgomery voters turn out at a higher rate than those in Prince George’s. In 2018, Montgomeryites were 18.0% of eligible Democrats but 20.0% of Democratic voters. Prince Georgians formed 21.0% of those eligible but only 20.2% of voters.

Today, Baltimore and its inner suburbs (Baltimore County, Anne Arundel and Howard) are have a slightly higher share of eligibles (40.6%) than the two big D.C. area powerhouses (39.1%). But unless Baltimore City ups its turnout game, the region’s share of Democratic primary voters will lag behind that of the inner D.C. suburbs as they did in 2018.

In the metropolitan areas, which include outer suburbs, Washington (46.7%) now has more eligibles than Baltimore (45.5%). In 2018, the Washington Metro already beat the Baltimore Metro in the share of all Democratic voters by over three points–47.8 to 44.6. This lead is likely to continue to slowly expand as D.C. is now growing faster than Baltimore and becoming even more heavily Democratic. In Montgomery, Trump’s share of the vote dropped from 33% in 2016 to 19% in 2020.

The Eastern Shore and the Western 3 (Garrett, Allegany and Washington) together form only 7.6% of eligible Democratic voters and are consequently almost an afterthought for statewide candidates except during the Tawes Crab and Clam Bake.

We’re also a long way from the days when the Baltimore area, let alone Baltimore City, dominated the state. Among Democratic primary voters, D.C. has already surpassed Baltimore with the lead looking to continue to grow slowly but steadily.