The products of Buckingham Ceramics, at least all of the ones I'm aware of, were manufactured by McCoy Pottery of Roseville, Ohio. Most of the pieces marked Buckingham Ceramics can also be found with a McCoy marking, and the relationship between the brands is unclear. It is possible that McCoy sold some products under the Buckingham label as a marketing tactic, perhaps to target different wholesale buyers. Buckingham could also have been an independent company that went to McCoy for production.