The pro-Union Better Together campaign group has received £1.6m in donations since April this year, it has been revealed.
Figures published by the group showed that the biggest donor, Argyll businessman Donald Houston, gave £100,000 and a further £500,000 through two of his companies.
Investment banker Andrew Fraser donated £200,000 and Alan Savage, chairman of Inverness-based recruitment group Orion, contributed £150,000. Author Christopher Sansom gave £133,000.
Since April more than 17,000 people have contributed to the campaign directed by Blair McDougall, mostly giving sums of less than £500.
The group has received almost £2.8m since it was established in May 2012.
Among the other donors listed this year are former banker and Arsenal chairman Sir Chippendale Keswick, who gave £23,000.
Mr Houston, director of the Adelphi Distillery in Ardnamurchan, said: "We have spent 300 years building a union between our countries that has achieved so much. Ripping up that union to satisfy the SNP is a ridiculous idea.
"The people of the Highlands that I speak with consider the SNP government in Edinburgh to be completely remote from our opinions and our way of life. They don't listen to what people have to say, they are only interested in breaking up the UK."
The entrepreneur, who donated cash through companies Beinn Bhuidhe and Rain Dance International, added: "I am in the fortunate position of being able to contribute financially to this incredibly important campaign.
"I hope that other people, in the same position as myself, are also willing to contribute whatever they can. This is the most important decision in the history of our country."
Mr Savage said: "My support for the Better Together campaign is stronger than ever following the publication of a White Paper that does nothing to convince me that independence would be a force for good for Scotland, Scottish people, the Scottish business community and the rest of our friends in the UK.
"Most people realise that we can have the best of both worlds in Scotland. We have a successful Scottish Parliament and the strength and security of being part of one of the largest economies in the world.
"In my opinion, separation would be a massive gamble and a huge folly."
Better Together director Mr McDougall said the group was "humbled" by the number of supporters who had contributed financially.
He said: "Even in tough economic conditions, thousands of people are playing their part in keeping Scotland a strong part of the United Kingdom.”
The SNP said the identity of the Better Together donors highlighted the "Tory roots" of the pro-Union campaign.
Angus Robertson MP, leader of the SNP in Westminster, said: "This list of donors to the No campaign is further proof that the anti-independence campaign is Tory to the core.
"It is led by a Tory Prime Minister and bankrolled by leading Tory party donors. "No wonder traditional Labour supporters and grassroots members are turning their backs on the No camp, which is simply a Tory front organisation funded by the same super-rich individuals who fund the Conservatives.
"Only a Yes vote offers a better future with the opportunity to build a fairer and more prosperous nation."
The Yes Campaign, the group campaigning for Scottish independence, said it will publish further information about donations it has received in due course.
A spokesman said: "It continues to be our policy to accept significant donations only from people who are entitled to vote in the referendum."
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