Three people who represented Maryland in the United States Senate were also former representatives of the 3rd district, including Ben Cardin, Barbara Mikulski, and Paul Sarbanes.

The district's previously odd shape was attributed to gerrymandering to favor Democratic candidates, following the 2000[3] and 2010[4] censuses.

[6] John Sarbanes, the previous Democratic Representative for the district, put forth the For the People Act of 2019 to address electoral reform, voting rights, and gerrymandering in the United States.

For the first time in decades, the district did not include Baltimore City or Baltimore County; meaning incumbent congressman John Sarbanes no longer lives in the district.

This latter fact explains why the district lost population, even though it, in theory, did not experience redistricting after the 1800 census.

[15] In the redistricting following the 1860 census, Maryland was reduced to five congressional districts.