While voting at an assigned polling place on Election Day may be the most common way to cast a ballot, it is not the only way. As a recent National Conference of State Legislatures article explains, the other methods are early, absentee, and mail-in voting.
In the 37 states (not including Connecticut) and the District of Columbia that allow early voting, voters can visit an election official's office or, in some states, a satellite location, such as a grocery store or library, and cast a vote without providing an excuse as to why they cannot vote on Election Day. Voting begins as early as 45 days before the election or as late as the Friday before the election, depending on the state.
Every state has some form of absentee voting, which allows voters to mail-in a paper ballot prior to Election Day. Twenty states, including Connecticut, require voters to provide an excuse for why they cannot vote on Election Day, while 27 states do not require one. Connecticut voters can find a list of acceptable excuses on the Secretary of the State's website.
Oregon, Washington, and Colorado conduct elections by mail, while 19 other states allow it in certain elections. Each registered voter is mailed a ballot prior to Election Day and must either return it by mail or drop it off at a designated location.