Most of us have at least a vague understanding of the political leanings of the communities we live in, but we tend not to know what fraction of our neighbors actually vote. I recently made a map showing what fraction of the population is registered to vote in legislative districts throughout the region.

Each district or ward is color-coded based on the percentage of residents who were registered voters in 2014; the darker the color, the more people who were registered. I only included Maryland and Virginia legislative districts that contain part of Prince George’s, Montgomery, Fairfax, or Arlington counties, or the cities of Alexandria, Falls Church, or Fairfax.

Because it was easiest to find data on registered voters for electoral districts, I decided to use lower house state legislative districts in Maryland and Virginia and wards in the District of Columbia for the map. (DC is split up geographically into eight wards, each of which has a representative on the DC Council.)

It is worth noting that while this data tells us what percentage of residents vote, it does not take into account the fact that not all districts have the same population of eligible voters. Unfortunately, I was unable to find data on the number of eligible voters, or of citizens eighteen or older, tabulated by legislative district.

One thing I think is noteworthy is how much the the percentage of residents registered to vote varies across the region. In Maryland’s District 47B, only 28% of the population is registered to vote (granted, the district does include the immigrant-heavy area of Langley Park), while in DC’s Ward 6 (which includes Capitol Hill), 86% of the population is registered to vote.

As a Prince George’s County resident, I was also surprised to find that the percentage of registered voters is generally lower in northern Prince George’s County than anywhere else in the DC area, since I had thought of the northern half of the county as more politically engaged than the south. However, the large immigrant communities in the northern county, and the associated larger numbers of non-citizens, are probably part of the reason for this effect.