The answer to this question must surely be very different depending on which person is asked. There are many different cultures just in the United States and so there are many people who could be seen as culturally different from ourselves.
For example, I live in a rural area. To me, people from the big cities on the coast are culturally different. They go to museums and buy all kinds of organic foods (at least that’s what many of the ones I know do) where I do not.
On the other hand, not all of the people around me are culturally similar. We have a large Hispanic population in my area. I would see many of the Hispanic people as culturally different. This is particularly true of those who are more recent immigrants.
Everyone will have a different answer to this question. Their answers will depend on how they identify themselves most strongly. Do they identify with others of their same race or ethnicity? Do they identify on with others on the basis of politics or religion? Their answers as to whom they find culturally different will depend on how they define themselves culturally.