Short answers, pulled from the story.
The first Star Wars Celebration was held at the Wings Over the Rockies Air and Space Museum in Denver, Colorado, from April 30-the 2nd of May 1999. The location was chosen because the Official Star Wars Fan Club, headed by Dan Madsen, was based in Denver. Over 20,000 fans attended.
Star Wars Celebration does not run on a fixed annual schedule, typically taking place every one to three years. It has been held in varying locations across the United States, Europe, and Asia.
Celebration Japan 2025, held from April 18-20, 2025, at the Makuhari Messe Convention Center near Tokyo, drew over 105,000 attendees, the highest recorded turnout in the event's history.
The first Star Wars Celebration held outside the United States was Celebration Europe, which took place in London from July 13-15, 2007, at the ExCeL Exhibition Centre. Around 30,000 people attended.
Harrison Ford made his first Star Wars Celebration appearance at Celebration Orlando 2017, joining the opening panel on the 13th of April 2017, alongside composer John Williams and other franchise figures.
Lucasfilm revealed both the teaser trailer and the official title for Star Wars: The Rise of Skywalker at Celebration Chicago 2019 on April 12. The event also brought the debut trailer for Star Wars Jedi: Fallen Order and first footage of The Mandalorian.