At the Constitutional Convention in 1787, delegates disagreed on the means of choosing the President. Some delegates wanted the President to be elected directly by the people while others opposed this idea. The disagreement resulted in yet another compromise. The delegates took the idea of people electing the President directly, and the idea of representative democracy, and fused them together to make the Electoral College. .
As I said before the great minds which formed this country (the delegates) had numerous different ideas on how the President would be elected. Most thought that the people should have direct power and directly. But others opposed the idea because they were uncertain and afraid of relying on the people to elect an official that would serve as President. This was because they thought the people would elect someone that might be against the ideas and opinions of those with all the money and power. So a compromise was made so that the people would have some direct involvement with electing the President but wouldn't have full power. This compromise was soon known as the Electoral College.
The Electoral College is a small group of people called electors, which in the end have the final say in who becomes President. How you might ask? When people go out on election day and go vote for there favorite candidate or who they think would do a good job, their vote (the popular vote) doesn't directly effect who becomes president, instead it gives the electors power to vote on who they think should be president. After the public election, the Electoral College meets and elects the President. .
The Electoral College is made up of 538 electors. Now this is where congress comes in, the 435 members of The House of Representatives and the 100 members of congress make up 535 of the electors. The other three? Washington D.C., they are not considered a state so they don't have any representatives in the House or and senators in the Senate, and are not allowed to participate in elections, so to be fair congress decided to give them 3 electoral votes.