Over the years ATC Trading Sessions took place at many places in different countries. After i while i lost track of all the events - but here are some places where Trading Sessions are being hold for a long time on a regular basis, the first two since 1997 without a break, some others for over ten years:
zurich, switzerland - calgary, canada - regina, canada - milwaukee, usa - naskup, canada - kelowna, canada - vancouver, canada - genève, switzerland
some for a period of time or only once:
alexandria, canada - arnhem, netherlands - bellingham, canada - biel/bienne, switzerland - boulder, co, usa - bregenz, austria - buenos aires, argentina - calgary, canada - denver, usa - edmonds, usa - emeryville, usa - genève, switzerland - hamburg, germany - kelowna, canada - lausanne, switzerland - lethbridge, canada - lynwood, usa - lyons, usa - milwaukee, usa - naskup, canada - nijmegen, netherlands - ottawa, canada - oulu, finland - parksville, bc, canada - philadelphia, usa - pilot butte, sk, canada - port adeleide, australia - portland, usa - regina, canada - richmond, canada - sechelt, canada - shawville, canada - siegershausen, switzerland - sonvilier, switzerland - stuttgart, germany - tampere, finland - tauranga, new zealand - toronto, canada - toulouse, france - turku, finland - vancouver, canada - vernon, canada - victoria, bc, canada - wakefield/la peche, canada - waltensburg/vuorz, switzerland - winnipeg, canada - zurich, switzerland
plus there were many others i heard of but never got further information. and there might be many others i never heard of.
Feel free to inform me about your ATC Trading Sessions!