Keeping up to speed as America decides
Finally America decides. After months of bluster, name calling and very little in the way of policy debate, 120 million people across the United States will go to the polls today to decide whether they want Donald Trump or Hillary Clinton to become the 45th President.
The voting is nothing like the system in Ireland
All 50 US states and Washington DC have a set number of "electors" in the electoral college - roughly proportionate to the size of each state.
California, the largest state, has 55 electoral votes, while sparsely-populated Wyoming and tiny Washington DC get only three each. There are 538 electors and to win a majority and become president either candidate needs to accumulate 270 electors - half the total plus one.
The number of electors is also equal to the number of seats it has in the House of Representatives and the Senate. All but two states, Maine and Nebraska, use a winner-takes-all system, so if you win the most votes in a state you take its entire haul of electoral college votes.
This means it's possible to win the popular vote but not the election.
Watch the swing states
This time it's Florida, Ohio and Pennsylvania. In recent cycles, the presidency has been won in Florida and Ohio. The two states also have near-perfect records of picking the president over the past five decades.
The result in Ohio has mirrored the national outcome in every election since 1960, while Florida has diverged from the nation at large just once over that period.
Other important states include Wisconsin, New Hampshire, Minnesota, Iowa, Michigan, Nevada, Colorado and North Carolina.
Both Hillary Clinton and Donald Trump have been working their way through these states in the last few days.
Take note of the newer battles
Because of demographic shifts in the US, paired with Mr Trump's unpopularity, states that were once solidly Republican are now within reach for the Democrats in 2016.
The Democratic nominee hopes to expand the map with wins in Arizona, Georgia and Missouri, all of which have consistently voted Republican for nearly two decades.
Because of the realities elsewhere on the map, Mr Trump cannot afford to let those states change hands in 2016.
Clinton looks likely to hold on to Colorado, Pennsylvania and Virginia, with Iowa and Nevada still hanging in the balance.
She is also facing a stronger-than-expected challenge in New Hampshire, which has voted for the Democrat in every recent election except 2000.
Don't assume the race is run
Most of the polls suggest there's still a lot to play for, although Clinton is still the frontrunner. It could even be a tie, with both candidates stuck at 269, in which case the House of Representatives would vote to choose the next president.
Voters are not just casting ballots for the president
As well as voting for president, Americans are also electing all 435 members of Congress's lower house, the House of Representatives, and one-third of the Senate. Plus, they are voting for a medley of local and state officials.
What's the link between the Pope and the way America votes?
When America's founding fathers created the electoral college system in 1787, there was no way a presidential candidate could mount a national campaign - and there was little in the way of national identity.
Election of the president by Congress was rejected as it was thought to be too divisive. Likewise, electing a president by state legislatures was discounted as it could have eroded federal authority. Electing the president by direct popular vote was also vetoed over fears people would vote for their favourite local candidate and no president would emerge with a popular majority sufficient to govern the whole country.
The system of electors, based loosely on the Roman Catholic College of Cardinals selecting the Pope, was chosen with the theory that the most knowledgeable and informed individuals from each state would select a president on merit, not state loyalties.
Watch the projections
As soon as polls close, there will be a projection for that state based on opinion polls carried out throughout the day. We will get our first projections from east coast states. There may be a dozen states where it's too close to call based on exit polls, and in those states the TV networks will make no projection.
Keep an eye on the clock
Polls open as early as 6am in the US. Donald Trump and Hillary Clinton are both expected to cast their votes in New York. Around midnight Irish time, polling stations start to close and first state projections will be made. Everybody, including the candidates, will be glued to the main TV networks who are usually the first to 'call it'. The earliest possible time to have a serious projection is around 4am Irish time.
Both candidates have booked New York venues for a 'victory party'. Mrs Clinton has a convention centre capable of hosting tens of thousands, whereas Mr Trump is being more low-key in the Midtown Hilton Hotel.
How can I tune in?
The Independent.ie online team will have minute-by-minute updates on the live blog, which begins at 1pm today and continues into Wednesday morning. INM Group Political Editor Kevin Doyle will report from the US throughout the day and night. The group's political staff will also contribute as results from individual states come through.
RTÉ will be broadcasting an election special at 11.25pm tonight, which runs until 3am. The national broadcaster will resume coverage at 9am on Wednesday morning.
UTV Ireland will present a special live from Washington DC from 10.40pm on.