The University of Nevada-Las Vegas is set to host the third and final of this year's three presidential debates on Wednesday, Oct. 19, 2016. Here are important details known about the event so far.

DONALD TRUMP VS. HILLARY CLINTON

This showdown between the Republican and Democratic presidential nominees is the last major scheduled event of the campaign. It comes as Clinton leads Trump in national polls by an average of 6.5 points, according to RealClearPolitics.

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Their first debate at Hofstra University on Long Island on Sept. 26 set a record as the most-watched debate in history with an estimated 84 million viewers, according to Nielsen. The audience for round two was smaller: an estimated 66.5 million.

Libertarian nominee Gary Johnson (7 percent) and Green Party candidate Jill Stein (2.2 percent) did not meet the 15 percent national polling threshold they needed to make the cut.

DEBATE SCHEDULE

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The debate begins at 9 p.m. Eastern time and ends at 10:30 p.m.

MODERATOR

The moderator is Fox News' Chris Wallace. "I don't believe my job is to be a truth squad," he has said.

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FORMAT AND TOPICS

The 90-minute debate will be divided into six segments of 15 minutes each.

Wallace has selected these topics: debt and entitlements, immigration, the economy, the Supreme Court, foreign hot spots and fitness to be president. Each will be the focus of one segment. However, the topics could change due to news developments, the commission says.

Wallace will begin each segment with a question, and each candidate will have two minutes to respond, before they respond to each other. The remaining time in the segment will be devoted to "a deeper discussion of the topic," the commission says.

HOW TO WATCH

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The debate will be widely available on broadcast and cable networks, and on livestreams.

HASHTAGS TO USE

There are two: #UNLVPresDebate and #UNLVegasdebate2016.

FUN FACT

Election Day is 20 days away — but by the time the debate gets going, about 2.2 million Americans already will have voted.