Castle to Cold Case
4 connections
Castle
Law & Order
Hudson University from L&O also appears as the home of various victims and crimes in Castle,
Homicide: Life On The Street
Law and Order and Homicide crossed over on four episodes
The X-Files
Homicide's John Munch questioned The X-Files' The Lone Gunmen.
Cold Case
Morley Cigrettes, the brand smoked by Cancer Man from the X-Files is smoked on Cold Case