Donald Trump is now hitting record high support in his run the 2016 Republican nomination, and now leads Texas Sen. Ted Cruz by 18 points in their race for the Oval Office.

A new Fox News national poll now has Trump registering 45 percent support among GOP voters and leading Cruz 45 percent to 27 percent. Ohio Gov. John Kasich closely trials Cruz at 25 percent.

Trump's widening lead comes just three weeks after the same poll found him leading Cruz by just three points at 41 percent to 38 percent. The 41 percent he registered last month previously stood as his highest level of support.

Trump's Biggest Support Comes From non-College Grads

A deeper analysis of the data finds Trump's most ardent support comes from GOP voters without a college degree. A robust 54 percent of all such voters openly voice their support for Trump. In addition, 50 percent of voters who self-identify as "very conservative" insist they plan to support the New York City real estate mogul and political neophyte. ...

Just as Trump's lead has grown wider, pollsters found the race between Democratic front-runner Hillary Clinton and Vermont Sen. Bernie Sanders has tightened.

Clinton, Sanders Race Grows Tighter

According to the poll, Clinton now leads Sanders 48 percent to 46 percent. Just last month, before Sanders ran off eight wins in nine primaries, Clinton led Sanders 55 percent to 42 percent.

Researchers found the biggest shift in the trajectory of that race comes from among female voters, where Clinton's support has recently declined by 11 points and Sanders' has surged by nine.

When it comes to potential general election match-ups, Clinton leads Trump and Cruz by an average of four points, but trials Kasich 49 percent to 40 percent.

Meanwhile, Sanders leads Trump and Cruz by an average of 13 points, but that lead shrinks to just four points when he is pitted against Kasich.

Yet, when asked which Republican has the best chance of knocking off Clinton, GOP voters pick Trump first at 42 percent, followed by Cruz at 24 percent and Kasich at 20 percent.

"When it comes to electability, the disconnect between what Republicans think and what polling data show is astounding," said Republican pollster Daron Shaw.

With voters set to go to the polls in New York on April 19, a recent Baruch College poll shows Trump now hitting 60 percent support and leading Cruz by a stunning 43 points.