The 2016 Republican presidential primaries and caucuses were a series of electoral contests organized by the Republican Party to select the unknown number of delegates to the Republican National Convention held in Summer 2016 and determine the nominee for President of the United States in the 2016 presidential election. The elections took place within all fifty U.S. states, the District of Columbia, and five U.S. territories and occurred between January and June 2016. The convention also approved the Party's platform and vice-presidential nominee.
The only candidate who ran in the primaries (that we know of) is Arizona Senator Bill O'Brien, who achieved the nomination. It is unknown whether or not he had any opponents.
In Summer 2016, the Republican National Convention officially nominated O'Brien for President and New Mexico Senator Laura Montez for Vice President. The election ended in an electoral tie, and the vote in the House tied, going to a vote in the Senate in which Montez becomes President. Montez was inaugurated on January 20, 2017.