Indiana's 1st congressional district is an electoral district for the U.S. Congress in Northwestern Indiana. The district is based in Gary and its surrounding suburbs and exurbs. It consists of all of Lake and Porter counties, as well as most of the northwestern part of LaPorte County, on the border with Michigan. Redistricting passed by the Indiana General Assembly in 2011 shifted the district's boundaries, effective January 2013, to include all of Lake and Porter counties and the western and northwestern townships of La Porte County, while moving Benton, Jasper and Newton counties out of the district.
The district is currently represented by Democrat Frank J. Mrvan. He was sworn in on January 3, 2021. The district's character is very different from the rest of Indiana. It includes almost all of the Indiana side of the Chicago metropolitan area. While Porter and LaPorte are Republican leaning counties, Lake County is more Democratic. Lake County contains two-thirds of the district's population. The district has not elected a Republican to Congress in 96 years, making it one of the longest continuously Democratic districts in the nation. Among Indiana's congressional districts, only the Indianapolis-based 7th district is more Democratic.
The 1st district includes the entirety of the following counties, with the exception of LaPorte, which it shares 2nd district. LaPorte townships within the first district include Coolspring, Michigan, New Durham, Scipio, Springfield, and most of Center.
As of 2021, Indiana's 1st congressional district is composed of Lake (pop. 496,005) and Porter (pop. 164,343) counties as well as part of LaPorte County (pop. 111,467), which is also partly within Indiana's 2nd district. Michigan City and five townships (Clinton, Coolspring, Dewey, New Durham, and Springfield) exist entirely in the 1st district. La Porte and eleven townships (Hanna, Hudson, Johnson, Lincoln, Noble, Pleasant, Prairie, Scipio, Union, Washington, and Wills) are split between the 1st and 2nd districts by Indiana West 500N and Indiana South/North 600W.
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