The Electoral College was established in Article II of the US Constitution by the founding fathers as a compromise between a popular vote and having Congress choose the president. To win the presidency, a candidate must obtain 270 electoral votes. There have been five times in US history when a candidate won the popular vote but did not win the Electoral College and therefore lost the election.

For more information, read the top 3 pros and cons of using the electoral college.

Source: National Archives and Records Administration, "U.S. Electoral College," archives.gov (accessed Sep. 30, 2019)