For centuries, Brandon in Suffolk was the centre of the gunflint industry in Britain because of the high quality flint found in the area. The town was a major exporter, including to colonial America, along with gunflints from France, Spain and the Netherlands.
America doesn't have any true flint by geological definition apart from 'Niobrara Blue' coming principally from Kansas. The way the term 'flint' is generally used in America came from a non-geological distinction between cherts of differing quality, with the term 'flint' being used for the higher qualities.
Geologically they aren't the same thing, although flint is regarded as a type of chert but coming from specific sedimentary origins of a type not common in America.
