But it's not just on the night itself that the city goes spookily mad. There's a 10-day build-up of events – cultural, sporty, educational, creepy and just plain silly – to make sure everyone, no matter their age, is well and truly aware that the 31st approaches.
It's a really great programme (full details at www.derrycity.gov.uk/halloween).
Among the events that caught my eye were the Ghostbusters Tours (two or three per evening 26th to 30th) Tel 028 7126 7284; Traditional Halloween Games at Gransha Wood, 28th, 3-7pm Tel: 028 7126 2664; The Park After Dark at Creggan County Park, 29th, 7pm Tel: 028 7136 3133; Spooky Sports, at The Diamond Centre, Claudy, for pre-schoolers on 28th 10-noon, and at St Columbs Park Leisure Centre, for 6-11 year olds 29th 10am-2.30pm Tel: 028 7136 1566; and Ghost Stories at the Playhouse, 29th 8pm Tel: 028 7126 8027.
Discover more about the origin of Halloween and other Celtic holidays.