House Retirements 2020

In every election cycle a certain number of representatives retire or run for other offices leaving behind open seats for their parties to defend. Here are the number of retirements in recent years:

Year Democrats Republicans
2018 18 34
2016 8 20
2014 16 25
2012 23 20
2010 17 20
2008 6 27
2006 9 18

This cycle, 12 Democrats, 36 Republicans and 1 Libertarian are retiring at the end of their current term.
Here are the announced retirements, sorted on PVI (Cook Partisan Voting Index).
Any seat between R+5 and D+5 is a swing district that has to be fought over, even more so if occupied by the "wrong" party.

Representative Party District PVI Reason for retirement
Mac Thornberry Republican TX-13 R+33 If he can't be a high-ranking committee member anymore, he's not interested.
Mike Conaway Republican TX-11 R+32 If he can't be a high-ranking committee member anymore, he's not interested, either.
Doug Collins Republican GA-09 R+31 Running for Kelly Loeffler's Senate seat
David Roe Republican TN-01 R+28 He is a doctor and has long been unhappy in the House
John Ratcliffe Republican TX-04 R+28 He resigned to become Donald Trump's Director of National Intelligence
Tom Graves Republican GA-14 R+27 Illness: He's sick of Donald Trump
Roger Marshall Republican KS-01 R+24 He is running for Pat Roberts' Senate seat
Rob Bishop Republican UT-01 R+26 If he can't be a high-ranking committee member anymore, he's also not interested.
John Shimkus Republican IL-15 R+21 He doesn't like being in the minority
Martha Roby Republican AL-02 R+16 Alabama may lose a district in 2020
Bradley Byrne Republican AL-01 R+15 He is running to unseat Sen. Doug Jones (D-AL)
Ralph Abraham Republican LA-05 R+15 He promised to serve only three terms and did that
Mark Meadows Republican NC-11 R+13 Became Trump's chief of staff
Francis Rooney Republican FL-19 R+13 He doesn't want to be on board the S.S. Trump anymore
Paul Mitchell Republican MI-10 R+13 He hates the bitter partisanship in D.C.
Jim Sensenbrenner Republican WI-05 R+13 He's 76 and has been in Congress over 40 years. What's the point of staying?
Bill Flores Republican TX-17 R+12 God and his wife told him to spend more time with his family
Duncan Hunter Republican CA-50 R+11 Hunter had to resign because he's moving from the House to the big house
Greg Gianforte Republican MT-AL R+11 Gianforte is running for governor of Montana
Greg Walden Republican OR-02 R+11 He doesn't relish another two (or more) years in the minority; too moderate for the modern GOP
Steve King Republican IA-04 R+11 Primaried
Steve Watkins Republican KS-02 R+10 Primaried
Pete Olson Republican TX-22 R+10 Olson was facing a rematch of a race he nearly lost in 2018
Ted Yoho Republican FL-03 R+9 Said he would serve only four terms, and is going to stick with that
Susan Brooks Republican IN-05 R+9 She is a moderate in a far-right party
Paul Cook Republican CA-08 R+9 He is running for San Bernadino Board of Supervisors [sic]
Kenny Marchant Republican TX-24 R+9 He would probably lose
Rob Woodall Republican GA-07 R+9 He would probably lose
Denver Riggleman Republican VA-05 R+6 Primaried
Ross Spano Republican FL-15 R+6 Primaried
Scott Tipton Republican CO-03 R+6 Primaried
Justin Amash Libertarian MI-03 R+6 Amash left the Republican Party in protest of Donald Trump, then announced his retirement
Peter King Republican NY-02 R+3 At 75, says he's weary of the job
Will Hurd Republican TX-23 R+1 He would also probably lose, and is also a moderate in a far-right party
Dave Loebsack Democratic IA-02 D+1 He originally planned to serve only 12 years, but stayed 2 more
George Holding Republican NC-02 D+4 Redistricting took his R+7 district to D+4, and Holding decided reelection was not possible
Denny Heck Democratic WA-10 D+5 He misses his wife and is weary of being in Congress
Dan Lipinski Democratic IL-03 D+6 Primaried
Nita Lowey Democratic NY-17 D+7 She's 82 and has been in Congress 31 years
Pete Visclosky Democratic IN-01 D+7 Democrats are moving too far left for his taste
Ben Ray Luján Democratic NM-03 D+8 Running to replace retiring Sen. Tom Udall (D-NM)
Joe Kennedy Democratic MA-04 D+9 Kennedy is challenging Sen. Ed Markey in the Democratic primary
Mark Walker Republican NC-06 D+11 Redistricting took his R+9 district to D+11, and Walker decided reelection was really not possible
Susan Davis Democratic CA-53 D+14 She says she wants to live at home in San Diego
Tulsi Gabbard Democratic HI-02 D+19 Says she wanted to focus on her unsuccessful presidential bid
Eliot Engel Democratic NY-16 D+24 Primaried
William Lacy Clay Democratic MO-01 D+29 Primaried
Jose Serrano Democratic NY-15 D+44 Serrano has Parkinson's disease