Yeah, everyone else already dropped out, but The Associated Press says he just reached the required number of delegates to lead his party.
By Kenrya Rankin May 26, 2016
 
      The Associated Press—which keeps the delegate tally that American press uses to track the presidential election—just announced that Donald Trump has amassed enough delegates to officially make him the Republican party’s presumptive nominee for president. He needed to collect 1,237 delegates to win, and AP reports that he has 1,238 (88 of them are unbound delegates).
Trump is the only candidate still in the race on the Republican side of the election. Before he hit the magic number, his party had an opening to nominate another candidate at the upcoming convention. This news makes that scenario unlikely, unless the unbound delegates remove their support.
Looking to the Democratic race, AP says Hillary Clinton has 2,305 of the 2,383 delegates (and superdelegates) she needs to garner her party's nom. Bernie Sanders has 1,539.