It has been vacant since Democrat Sarah McBride, who succeeded fellow Democrat Harris McDowell III in 2020, resigned in 2025 to become a United States Congresswoman.

[3] McBride is the first openly transgender state senator in American history.

[4] District 1 covers the northeastern tip of New Castle County along the Delaware River, including Claymont, Bellefonte, most of Edgemoor, and parts of northern Wilmington.

[7] The district borders New Jersey via the Delaware River and Pennsylvania via the Twelve-Mile Circle.

[1] Delaware Senators are elected to staggered four-year terms.