Rep. Jim MathesonJames (Jim) David MathesonTrump's budget targets affordable, reliable power Work begins on T infrastructure plan New president, new Congress, new opportunity MORE (D-Utah) will run for reelection, his office has confirmed to The Hill.

Matheson, the co-chairman of the fiscally conservative Blue Dog Coalition, had been weighing a run for governor after state Republicans targeted him in redistricting. Matheson's decision gives Democrats by far the best chance of holding his seat.

"The political boundaries of the district may be arbitrary, but the people, the communities and their priorities are real and well-known to me," Matheson said in a statement Thursday.

His current district is the most heavily Republican of any held by a Democrat. The state added a congressional district, and the new district encompasses chunks of his base in Salt Lake City as well as rural portions of the state. The district does not include his home and becomes a bit more conservative than the one he's held on to for years.

Matheson will likely be a top Republican target, and three Republicans are already running in the district. On Wednesday, Matheson downplayed concerns about a difficult reelection.

"Blue Dogs are used to facing challenging races, and after the wave election of 2010, those Blue Dogs that are still here know how to survive," he said on a Wednesday conference call.

— This post was updated at 2:50 p.m.