The franchise moved off this world for the next entry for Leprechaun 4: In Space. Needless to say, there aren’t any real exterior locations to visit for this one.
This Leprechaun location series is featured in Horrors Hallowed Grounds in the March 2018 issue of HorrorHound Magazine. Below are links for each film:
This film was shot in 18 days at the Front Street Studios in Burbank.
The closest I could to a 'location' shot is the effects shop in Sylmar featured in the behind-the-scenes video.