AP
After nearly 18 months of campaigning, attempts to expand the typical Republican electoral map, and battles to hang on to traditional Republican strongholds, Trump heads into Tuesday with little room for error.
But his swing upward over the past few weeks, combined with Democratic nominee Hillary Clinton's struggles amid a brutal barrage of bad news, has given Trump an opening.
Trump's path relies on a combination of swinging industrial Midwest swing states red and holding on to states that have leaned Republican in recent elections.
His chances remain slim: the data-journalism site FiveThirtyEight provides Trump with about a 35% chance of winning. That's on the higher end of the scale - Princeton University professor and data-scientist Sam Wang, for instance, gives him about a 1% chance.
Here's a look at Trump's three most plausible paths (maps via 270toWin.com).