Republicans have a 33-16 advantage in gubernatorial offices; Alaska's Bill Walker is an independent. The most competitive of 2018's 36 gubernatorial races:
Colorado
Democratic Gov. John Hickenlooper is term-limited. The field of candidates in both parties is expected to be large and the competition to be wide open. The state has trended Democratic in recent elections. Primaries are June 26.
Connecticut
Gov. Dannel Malloy, a Democrat, decided not to seek a third term. There are no clear front-runners as Democratic Lt. Gov. Nancy Wyman and House GOP Leader Themis Klarides weigh their plans. Primaries will be Aug. 14.
Florida
Gov. Rick Scott, a Republican, can't run again because of term limits. Democrats last won the governorship in 1994, but recent contests have been narrowly divided. Climate change is a big issue. Primaries are Aug. 28.
Illinois
First-term Gov. Bruce Rauner, a Republican in a Democratic state, is running. He has fought with the Democratic Legislature over spending; the state may end 2017 with a $6.2 billion deficit. Primaries are March 20.
Iowa
GOP Gov. Terry Branstad left to become U.S. ambassador to China. GOP Lt. Gov. Kim Reynolds succeeded him and is the state's first female governor. She wants a full term. Primaries are June 5.
Maine
Republican Gov. Paul LePage is term-limited. Maine hasn't had consecutive governors from the same party since 1958. Voters endorsed ranked-choice voting in 2016, but the state Supreme Court said the Legislature must approve it. Primaries are June 12.
Michigan
Republican Gov. Rick Snyder is term-limited. He alienated Democrats with his handling of the Flint water crisis and right-to-work legislation, but Republicans have controlled the governorship and Legislature for eight years. Aug. 7 primaries.
Nevada
Republican Gov. Brian Sandoval is term-limited. GOP Attorney General Adam Laxalt is already running TV ads in the race to succeed him. Nevada went Democratic in the 2016 presidential race, but the GOP swept 2014 midterms. Primaries are June 12.
New Mexico
Republican Gov. Susana Martinez is term-limited. A recent poll found U.S. Rep. Michelle Lujan Grisham with a big lead among Democrats. She and GOP Rep. Steve Pearce raised more than $1 million each in six months. June 5 primaries.
Pennsylvania
Democratic Gov. Tom Wolf said he'll run for a second term; he will face primary challengers. Hillary Clinton's loss in 2016 might be a bad sign for Democrats. There's already a big GOP field. May 15 primaries.
