Devotees travelled from across the country to attend the three-day event, which was held just outside of London, but the convention was marred by the shocking news of Monteith's death on Saturday (13Jul13).
The event, which featured appearances from castmembers including Curt Mega, Riker Lynch and Dominic Barnes, became a memorial for Monteith as tearful fans celebrated his life and work.
Convention-goer Chloe-Louise Bond, 22, tells the Associated Press, "We all woke up to hear the story, and no one really wanted to believe it was true. Walking into the main room (at the convention), you could just feel the tragedy in the air, absolute strangers became a family right in that moment. Everyone was crying and hugging and just trying to get over the shock."
Devotees were seen hugging, weeping and singing songs from the show, and the actors shared their memories of working with the late star during a panel discussion.
Curt Mega, who played Dalton Academy student Nick, told the audience about his time on the Glee Live! Tour, revealing Monteith wanted to shun the offer of first class travel in favour of riding with the less famous castmembers on the tour bus, saying, "All the main cast would fly on a jet everywhere they went and we were like, on a bus... He (Monteith) came over one night and was like 'I heard your bus is super cool and I want to check it out'. He was like, 'Dang! I don't wanna be on a plane any more, I wanna crash with you guys'."
The talk ended with a minute's silence held in honour of Monteith, followed by a group hug.
Fans in Canada have also been memorialising the actor by leaving floral tributes and messages of condolence outside the hotel in Vancouver, where his body was found on Saturday, while Monteith's representatives have urged devotees to show their sadness by making a donation to a charity he helped launch last year (12).
Donations can be made to the Project Limelight Society, an organisation which offers free performing arts classes for children from Vancouver. Monteith launched the charity with his former acting teacher, Maureen Webb, who was one of the last people to see the star before his death as they enjoyed dinner together on Thursday (11Jul13).