Maine's 2nd congressional district is a congressional district in the U.S. state of Maine. Covering 27,326 square miles (70,770 km²), it comprises nearly 80% of the state's total land area. The district comprises most of the land area north of the Portland and Augusta metropolitan areas. It includes the cities of Lewiston, Bangor, Auburn, and Presque Isle. The district is represented by Democrat Jared Golden, who took office in 2019.

It is the largest district by area east of the Mississippi River, and the 24th largest overall. It is the second-most rural district in the United States, with 72% of its population in rural areas, and it has the second highest proportion of non-Hispanic White residents (94%); only Kentucky's 5th congressional district exceeds it in the two categories.^[2] Furthermore, it is the only district in New England that voted for Donald Trump in 2020. Additionally, it was one of five districts that would have voted for Trump in 2020 had they existed in their current configuration while being won or held by a Democrat in 2022.

Until the Missouri Compromise was reached in 1820, Maine was a part of Massachusetts as the District of Maine. When it became a state in 1820, Maine had seven congressional districts credited to it (Massachusetts including Maine had been given 20 districts after the 1810 census). Since Maine became a state, all but two districts have been reallocated to other states.

In 2018, the district became the first in the United States to elect the ranked choice winner over the first-past-the-post winner, after a referendum in 2016 changed Maine's electoral system from the latter system to the former. Incumbent representative Bruce Poliquin won a plurality of the first preference votes. However, the second and third preferences from two independent candidates flowed overwhelmingly to Jared Golden, allowing him to win with 50.6% of the vote once all preferences were distributed.

Historically, the district has tended to keep its incumbents regardless of party. When Golden defeated two-term Republican incumbent Bruce Poliquin in 2018, it was the first time an incumbent had lost reelection in the district since 1916.^[3] Since 1965, the district's representatives have frequently sought statewide office. Three U.S. senators (Democrat William Hathaway and Republicans William Cohen and Olympia Snowe), one governor (Democrat John Baldacci), and one nominee for governor (Democrat Mike Michaud) all previously held the seat. Due to its size, the district's congressman is usually reckoned as a statewide figure; its footprint includes portions of all three television markets anchored in the state.

In US presidential elections, most states give all the state's electoral votes to the candidate that wins the statewide popular vote. This is a type of winner-takes-all voting. Maine and Nebraska instead use the congressional district method, where the winner in each of the state's congressional districts gets one electoral vote, and the statewide winner gets an additional two electoral votes. Since Maine introduced this system in 1969, Maine's second district voted the same way as the entire state of Maine for every election until 2016 and 2020.

• Maine's congressional districts
• List of United States congressional districts