Palace Diner What is this? Close icon Rating Scale Number Description 5 Excellent 4 Very Good 3 Good 2 I am not in a rush to return 1 I will not be going back Palace Diner is the oldest diner in Maine. It originally opened in 1927 and is now owned by Greg Mitchell and Chad Conley. Palace Diner, Franklin Street, Biddeford, ME, USAWebsite | Map