A sea of saltires waved as the crowds listened to musical performances and speeches from campaigners.
The rally, organised under the Voice Of The People banner, comes just over a week after Scotland rejected independence in the referendum.
Many of those in attendance were still sporting badges, signs and banners in support of the Yes campaign, which won 45% of the vote on September 18.
They joined in with renditions of Flower Of Scotland and Caledonia, while speakers urged them to carry on with the campaign.
Those addressing the crowd included SNP MSP Marco Biagi and Kate Higgins of the Women For Independence group.
Ms Higgins urged people to reach out to the older female generation who may have voted No, and to take the campaign into deprived communities across Scotland.
“It’s not over,” she told the crowd.
“The dream will never die as long as we have gatherings like this.”
Mr Biagi rallied supporters, stating: “True power has not been given back to Westminster, it has been lent to them and one day we will take it back.”
Those attending were encouraged to give their backing to the SNP, with the party continuing its recruitment drive by making membership forms available at the event.
The SNP - alongside other pro-independence parties - has seen its membership dramatically increase in the wake of the referendum.
Meanwhile, another campaigner called on people to sign a petition calling for a “revote of the Scottish Referendum, counted by impartial international parties”. The petition on change.org has been signed by more than 93,000 people.
A second rally, focusing on the demand for a revote, will be held outside Holyrood tomorrow. More than 9,000 people have stated they plan to attend on the event’s Facebook page.
A third rally, dubbed The 45 Plus Rally, will be held outside the Parliament on November 29, with 32,000 people stating they are going on Facebook.
Other rallies have been organised via social media in various parts of Scotland, including Glasgow and Aberdeen.