Technically, on election day Americans are not voting for the presidential candidates themselves, but 'electors', who pledge to vote for a particular candidate. In most cases the electors' names are not on the ballot.

In nearly every state, whoever wins the most votes also wins all of that state's electors - who take part in a process known as the 'electoral college'.

Each state has a different number of electors based on the number of representatives and senators it has in Congress, which itself is decided by the size of its population.

A large, populous state like California has 55 electors, whereas a large, sparsely populated state such as Montana has only three.

To win the election, a candidate must win an absolute majority of electors. There are 538 available in total, so 270 are needed to winThe process by which electors are chosen varies state by state.
The electors meet in their state capitals on the Monday after the second Wednesday in December and - almost always - cast their ballots according to their state's popular vote result.

The results are certified and sent to Washington.
The new president is inaugurated in January.

Why are certain states 'key battlegrounds'?

The presidential race is usually decided in a few states which switch allegiance from election to election.

These are sometimes called battleground or swing states.

The swings are often down to changing demographics, or personal factors such as a candidate coming from that state or region.
Capturing the electoral votes of just one or two of these states can be enough to tip a candidate over the 270 needed to win.


Source: http://www.bbc.com/news/election-us-2016-37249697

President Trump. Congratulations

nathanspence:

Congratulations are not in order. It is not over until it's over

ok