The designated Trick or Treat hours in the City of Merrill are 5-8 p.m. on Thursday, Oct. 31. Trick or Treaters should follow this theme: On Halloween, Be Smart, Be Safe, Be Seen! Merrill Police officers will be patrolling the streets to make sure everyone is safe while collecting their treats. If you see an officer, wave at him or her, and they might just have a treat for you!