90% of the crowd during the sequence at St. Peter's Field were digitally duplicated and created; in reality, there was 200 extras. The sequence was filmed at Tilbury Port, and many of the buildings were also added in post-production, re-created from historical records.
Production used the Tarred Yarn Store and the exterior of the Ropery to double as a Cotton Mill in Manchester at the Chatham Historic Dockyard in Kent. St Mary's Marshes on the Isle of Grain also appears in a short scene at the beginning of the film, when a lonely figure is seen walking along the marshes.
The film was selected to be screened in the main competition section of the 75th Venice International Film Festival. The film received its UK premiere on 17 October 2018, as part of the BFI London Film Festival, in Manchester. The screening marks the first time the festival has held a premiere outside London. Leigh said he was delighted that Peterloo would be premiered "where it happened."