In Washington, Democratic former U.S. Rep. Jay Inslee led state Attorney General Rob McKenna 51 percent to 49 percent in the battle to succeed outgoing Democratic Gov. Chris Gregoire.
Control of the governor's office moved from one political party to the other in just one state so far, returns showed. Voters in North Carolina elected Republican Pat McCrory over Democrat Walter Dayton to succeed outgoing Democratic Gov. Bev Perdue, NBC said.
Six governors -- four Democrats and two Republicans -- were re-elected, while in three races for open seats, Democrats held two, and Republicans held one and took one open race.
Incumbent Democratic Gov. Jay Nixon defeated Republican challenger Dave Spence in Missouri, and West Virginia Gov. Earl Ray Tomblin turned back a challenge by Republican Bill Maloney, CNN reported.
Incumbent Democratic Delaware Gov. Jack Markell defeated Republican challenger Jeff Cragg, and voters in Vermont re-elected Democratic Gov. Peter Shumlin over GOP challenger Randy Brock, NBC News projected.
Incumbent Republican Gov. Gary Herbert was the winner over Democrat Peter Cooke in Utah, and Republican Gov. Jack Dalrymple defeated Democratic challenger Ryan Taylor in North Dakota.
In New Hampshire, NBC said Democrat Maggie Hassan defeated Republican nominee Ovide Lamontagne in the race to succeed outgoing Gov. John Lynch, a Democrat.
In Montana, Democrat Steve Bullock defeated Republican Rick Hill 49 percent to 47 percent, with 87 percent of precincts reporting, in the race to succeed outgoing Democratic Gov. Brian Schweitzer, CNN said.