By Rebecca Morin  |  [email protected]

It’s never too early.

As the filing period to run for state and federal office opened Monday — 100 days until the primary elections, several Democrats and Republican hopefuls are vying to overtake the incumbents in their district and even for the U.S. Senate. The last day to file is on March 18.

Here are all the incumbents and their challengers for the congressional races in this election, as of March 1:

1ST DISTRICT:
Incumbent:
Rod Blum, R-IOWA
The first-time incumbent will seek a second term. Rod Blum, 60, was elected in the 1st Congressional District after Bruce Braley vacated his seat to run for Senate. Blum,  a businessman, owns Digital Canal, a software company.

Challengers:

Monica Vernon, Democrat
Monica Vernon, a Cedar Rapids city councilor, ran for lieutenant governor during the midterm elections. She and running mate Jack Hatch lost to incumbents Terry Branstad and Kim Reynolds. Vernon announced her bid for Congress in January 2015.

Gary Kroeger, Democrat
Gary Kroeger, a former actor and “Saturday Night Live” cast member, announced he would run for the seat in April 2015. Kroeger is now an ad director in Cedar Falls.

Patrick Murphy, Democrat
This is the second time Patrick Murphy has gone up against Blum in the 1st District. Murphy was defeated in the 2014 midterm elections.

2ND DISTRICT:
Incumbent:
Dave Loebsack, D-IOWA
Dave Loebsack will seek his sixth term. Loebsack defeated 15-term incumbent and moderate Republican Jim Leach in 2006. Currently, the former Cornell College political-science professor is Iowa’s lone Democrat in Congress.

Challenger:
Mark Chelgren, Republican
Mark Chelgren will challenge Loebsack for the first time after the Iowa congressman beat Mariannette Miller-Meeks, former Iowa director of Public Health, for the third time in 2014. Chelgren is a state senator from Ottumwa.

3RD DISTRICT:
Incumbent: 
DAVID YOUNG, R-IOWA
David Young was first elected to office in the 2014 midterm elections, and he now seeks a second term. Prior to his tenure as congressman, Young was the chief of staff for to Sen. Chuck Grassley, R-Iowa, from 2006 to 2013.

Challengers:

Desmund Adams, Democrat
Desmund Adams, a Clive resident and businessman, is the first African American ever to seek federal office in the state. Adams filed his paperwork to compete in the 3rd District on Monday.

Jim Mowrer, Democrat
Jim Mowrer, an Iraq War veteran and former Pentagon aide, is running for Congress once again. In the 2014 midterm elections, Mowrer ran against Rep. Steve King in the 4th District.

Mike Sherzan, Democrat

Mike Sherzan is another hopeful not new to the election game. In 2014, Sherzan had a short campaign in the race for the 3rd District. The financial-services professional officially announced his campaign in December.

4th District:
Incumbent:
STEVE KING, R-IOWA
Steve King will seek his ninth term in Congress, representing one of the most conservative areas of the state. However, there have been talks that other Republicans mulling a challenge to King for his spot.

Challenger:
Kim Weaver, Democrat

In August 2015, Democrat Kim Weaver became the first in her party to announce that she will be running against King. She works in the Office of the State Long-Term Care Ombudsman and announced her candidacy at the Democratic Party’s Wing-Ding Dinner.