The electoral college is not a place, but a Constitutional process.

Under Article II of the Constitution, each state appoints electors equal to the number of votes the state has for representatives and senators.  Each state determines its own method for the selection.  In 1804, the Twelfth Amendment revised the  method for casting votes by the electors, so that each elector casts a vote for President and for Vice-President.

In 1824, no candidate received the required majority of votes by electors; at the time, a candidate needed 131 electoral votes.  Under the Twelfth Amendment, if  no candidate has a majority, the House of Representatives must vote to select the President and the Vice-President.  John Quincy Adams won the House vote, defeating Andrew Jackson who had won the popular vote.

The Twenty-third Amendment permits the District of Columbia to appoint electors in the same manner as the states.  DC now has three electoral votes, although no voting members of Congress.

Congress sets the dates for the choosing the electors and for voting; the dates are the same throughout the country.  This year, the electors meet in their respective states on December 17.  A candidate needs 270 electoral votes to win the election.

To read more about the electoral college, click here.  See also:

America Votes:  A Guide to Modern Election Law and Voting Rights

Bugh, Gary.  Electoral College Reform:  Challenges and Possibilities