However, final results from at least five of those contests may not be available for days, and in some cases, months.
With public disapproval of President Donald Trump weighing on Republicans across the country, voters are deciding whether to end the political careers of embattled Republican senators, including Trump ally Lindsey Graham of South Carolina and moderate Susan Collins of Maine, among others.
In total, 12 Republican-held seats and two Democratic-held seats are in play, based on a Reuters analysis of three nonpartisan U.S. elections forecasters - the Center for Politics at the University of Virginia, the Cook Political Report and Inside Elections.
McConnell was among a dozen incumbents from both parties to be declared early winners, as expected. McConnell overcame a challenge in Kentucky from Democrat Amy McGrath, a former U.S. Marine Corps fighter pilot who out-fundraised McConnell by $40 million but was unable to overcome the state's Republican sway.
MITCH MCCONNELL: The people of Kentucky had a clear choice, and they sent a clear message. Tonight, Kentuckians said that challenging times need proven leadership. And our nation will need Kentucky values and Kentucky ideas to defeat this virus and regain our footing.
So tonight, Kentucky said we're keeping our front row seat in the Senate. We don't yet know which presidential candidate will begin a new term in January. We don't know which party will control the Senate. But some things are certain already.
We know grave challenges will remain before us-- challenges that could not care less about our political polarization. We know our next president will need to unite the country even as we all continue to bring different ideas and commitments to the table. We also know beyond any shadow of a doubt that our nation and our people can do this.