In one scene, Castle makes an insulting crack about Canada to Beckett. Nathan Fillion and Stana Katic were both born and raised in Canada.
The Castle/Rogers home address is 595 Broome Street, New York, NY 10013 and Kate's home address is 2540 E. 3rd Street, New York, NY 10012.
Matt Letscher, who has a recurring role this season, is the older brother of Brian Letscher, who plays an Irish mobster in "The Wild Rover (2013)".
It's mentioned in previous episodes that Castle is poker buddies with James Patterson. Guest star Gina Ravera plays Naomi Cross, the niece of Patterson's most famous character, Alex Cross, in Kiss the Girls (1997).