Illinois Democrats on Friday proposed a new set of highly gerrymandered congressional maps that would consolidate Democratic power in the state’s congressional delegation, most likely cutting the number of Republican seats in the state to three from five.

The proposal would eliminate the Republican-friendly seat held by Representative Adam Kinzinger, a Trump antagonist and a Republican whose current district hugs the Chicago exurbs and parts of northern and central Illinois.

The maps, if approved by the state’s Democrat-controlled House and Senate, would be among the most gerrymandered in the country. Two districts, designed to elect Democratic candidates, would snake across hundreds of miles of rural areas to connect small Democratic-leaning communities. And 42 of the state’s 102 counties would be split up, according to an analysis from the Princeton Gerrymandering Project.

The current Illinois House delegation is made up of 13 Democrats and five Republicans. The proposal would most likely result in 14 Democrats and three Republicans. The state is losing a seat to reapportionment.

State lawmakers elsewhere in the nation have also sought to maximize their partisan advantages during the once-in-a-decade redistricting process. Oregon Democrats drew just a single Republican district among the six in their state’s new map. In Texas, Republicans are aiming to press their advantage to minimize Democratic districts.

The proposed 17th District of Illinois, represented now by Democrat Cheri Bustos, would stretch in a crescent along the state’s northwestern borders, connecting Rockford in the north to Peoria and the twin cities of Bloomington and Normal, home to Illinois State University. Driving the length of the district without leaving it would cover 332 miles.

The new map’s 13th District would connect the diverse suburban communities east of St. Louis, the state capital of Springfield and the college towns of Champaign and Urbana, more than three hours away by car.

The proposal leaves in place one of the nation’s crookedest districts, the jaw-shaped Fourth that connects Hispanic neighborhoods on the North and South Sides of Chicago. In the mouth of the proposed Fourth District sits the Seventh, one of three districts drawn to have a plurality of Black voters.

Mr. Kinzinger, a six-term congressman, has for months said he plans to seek re-election to the House and dismissed suggestions that he run for governor against the Democratic incumbent, J.B. Pritzker, or the Senate, against Senator Tammy Duckworth. But on Friday, with his home drawn into a Democrat-heavy district held by Representative Marie Newman, Mr. Kinzinger said he would consider seeking a different office.

“Following the release of the new congressional maps for Illinois, my team and I will spend some time looking them over and reviewing all of the options, including those outside the House,” Mr. Kinzinger said in a statement released by his office.

In a text message, Mr. Kinzinger said he was “just talking options” and declined to elaborate.