The 1990 IT miniseries, the 2017 IT movie, and 2019 sequel IT Chapter Two all brought Stephen King's Derry to life, and here's where they did it. While Pennywise the Dancing Clown is the character that rightfully gets the most attention from the IT franchise, with the Losers' Club a collective close second, there's something to be said for the fictional down of Derry, Maine being a character in and of itself. It's a very interesting place, explaining why it's popped up in several other King stories.
In IT, Derry is an extension of the monster itself, having long since been corrupted by its immense power and mental influence. This aspect is only briefly touched on in the screen adaptations of IT, but in the book, Pennywise holds sway over the town's inhabitants, explaining why so often the Losers' Club find themselves alone and terrorized in public situations that should rightfully lead to some kind of adult intervention. The adults of Derry are collectively under ITs spell.
As laid out in King's novel, Derry is the kind of small town that might look like a postcard on the outside, but underneath, hides decades of missing children, murder, disasters, hate crimes, and basically every type of human evil possible, and that's even before Pennywise physically gets involved. Derry is a town that's sick, but thankfully the places it was shot in apparently remain uninfected.
Where IT 1990's Derry Scenes Were Filmed
One thing the IT miniseries and the two later IT movies have in common is that they were all shot in Canada, because Hollywood loves tax breaks. The Derry scenes in IT 1990 were all shot in various area of British Columbia, mostly in Vancouver. The Barrens area, its surrounding lake, and its adjoining Pennywise lair were shot in Stanley Park, while the general town scenes were shot in New Westminster. The school attended by the Losers' Club is the real life St. Thomas Aquinas High School, and Beverly Marsh's house was a real house located on 417 Heatley Ave. The famous storm drain where Pennywise lures in Georgie is located at the intersection of 3rd St and Liverpool.
Where IT 2017 & IT Chapter Two's Derry Scenes Were Filmed
As mentioned, IT 2017 and IT Chapter Two also primarily filmed in Canada, but this time it was in Ontario, primarily Toronto and the small town of Port Hope. The infamous house on Neibolt Street was built at the intersection of James St and Eulalie avenue in Oshawa, Ontario, although the set has now been destroyed. The storm drain where Pennywise claimed Georgie's life this time out is at the intersection of Springmount Ave and William St in Toronto. The quarry scenes were shot at a real quarry called Elora Gorge, with this version of The Barrens was filmed at Rouge Park in Toronto. Interestingly, the sewer scenes were entirely shot on constructed sets at the Pinewood Studios facility in Ontario. Finally, Henry Bowers' house is a real house in Pickering, that was actually also used for Will Graham's home on Hannibal.