There's no unified black identity either though. There are millions of black people in both USA and Africa, but their cultures and lived experiences are so incredibly different. Not to mention the diversity within the country.
Obviously people in different states lead different lives. It's still possible to have a shared identity through facing similar struggles and discrimination.
Just because I grew up in IL and my cousin grew up in CA doesn't mean we can't have a shared identity as Romanian-Americans either.
edit: I have amended this and my parent post to clarify I meant a shared experience, not a unified one.