The Scottish independence referendum will be held on 18 September 2014, First Minister Alex Salmond has said.
He revealed the date as draft legislation on holding the vote was brought before the Scottish Parliament.
Voters will be asked the yes/no question, "Should Scotland be an independent country?"
The Scottish government said it was a historic day, but opposition parties accused the SNP of keeping voters in the dark for too long.
Scots ministers previously only said the referendum would take place in autumn 2014.
Announcing the date while speaking in the Scottish Parliament in Edinburgh, Mr Salmond said: "It's worth reflecting, just for a moment, on the privilege this nation and this generation will have - nothing less than choosing the future course of our country.
"We have been on a journey since 1999, since the restoration of our parliament here in the heart of our ancient capital. We've witnessed a growing confidence, an increase in democratic accountability.
"I'm honoured to announce that, on Thursday the 18th of September 2014, we will hold Scotland's referendum - a historic day when the people will decide Scotland's future."
Scottish ministers - who will publish their substantive case for independence in a white paper later this year - said a "Yes" vote would allow Scotland to use its natural assets to build a better country.
Scots opposition parties who support the Union - Labour, the Conservatives and Liberal Democrats, as well as the Westminster government - said Scotland was better off as part of the wider UK.
Mr Salmond said: "People will be able to choose if they want a Scotland that is independent and able to make her own decisions - with a Scottish Parliament that is responsible for making the most of Scotland's rich resources to benefit its communities and safeguard the welfare of our most vulnerable citizens and accountable for how we engage other nations around the world."
MSPs will need to approve the arrangements for the vote in the Scottish Independence Referendum Bill, although the SNP's parliamentary majority means the passage of the legislation is assured.
The Scottish government said the bill would make sure that:
- The referendum itself is preceded by a 16-week formal campaign period, during which limits will apply to the amount of money registered campaigners can spend, to ensure a level playing field for both sides of the debate.
- The vote is overseen by the independent Electoral Commission watchdog, which is responsible for regulating campaign rules and informing the public about the referendum.
- The ballot is conducted under the direction of a "chief counting officer", who will be responsible for appointing local counting officers.
Reacting to the date Johann Lamont, leader of Scottish Labour, said: "The truth is, Alex Salmond knows if he held the referendum now, he wouldn't just lose it, he would be routed.
"All the self-aggrandizement of today isn't just a sign of the first minister's usual pomposity.
"Making an occasion out of a delayed announcement is an attempt to con the people into believing that we have moved a step towards independence when we haven't."
Scottish Conservative leader Ruth Davidson welcomed the clarity provided by the date, adding: "I believe that, in September of next year, the people of Scotland will vote to stay within our United Kingdom.
"Recognising that the autonomy the Scottish Parliament has in areas such as health, social care education and justice, allied with the strength of being part of a larger UK family, the safety and security of our intelligence services, the international standing from our diplomatic corps and the advantages of being one of the largest economies in the planet means Scotland can make a positive choice for devolution - the very best of both worlds - not opt for separation."
Willie Rennie, the Scottish Liberal Democrat leader, told MSPs: "I'm sure the first minister is excited by today's events, but after all the build up, this looks like one of those occasions where the trailer's more exciting than the movie.
"It's taken the first minister almost 700 days to get the Cabinet to agree to the date of the referendum - why on earth does he think it will take him less time to break up the country?"
Green MSP Patrick Harvie, whose party supports independence, said: "Now we have the date for our diaries, the effort to persuade those who are undecided must focus on the needs of real people and not just those with loud voices and deep pockets."
Independent member Margo MacDonald, who also backs a "Yes" vote in 2014, said the level of debate must now be raised, telling the parliament: "This is about a country's soul - it's about your children and your grandchildren's standards and place in the world."
For the UK government, Scottish secretary Michael Moore welcomed news of the date, adding: "The debate about Scotland's future has already begun and will only intensify, and that is something I look forward to.
"I am confident when Scots go to the polls they will vote in favour of Scotland staying within a strong and secure UK family."
A special Scottish Parliament cross-party committee is to begin scrutinising the referendum legislation, and has asked interested individuals and organisations to submit their views.
The Scottish government has already introduced separate draft legislation to allow 16 and 17-year-olds to vote in the ballot.