The US is a mix of different European cultures and touches of other cultures in some regions. Hamburgers, pizza, enchilada's for simple minded examples?
I'm not talking (just) about who came on the mayflower, there has been influxes of immigrants since the founding of the nation. I currently reside in a part of town referred to as "German Village", which was settled primarily by German immigrants in the mid to late 1800's and continues to have places that serve "German" cuisine.
America from its founding was a place for people of all stripes to gather. It of course not only is a amalgamation of cultures but it has birthed its own cultures, some of which are associated with certain groups or regions: southern culture, new england culture, african american culture to name a few subcultures/groups--even the cultures we've birthed show diversity!