According to the US government there are 5 main races:

American Indian or Alaskan Indian
Black or African American
Native Hawaiian or Other Pacific Islander

and 2 main ethnicities:

Non Hispanic/Latino

The ethnicity question should always be asked first, then the race question.

(I work in public health, and have to deal with this stuff ALL the time.)
"I don't know! I don't know why I did it, I don't know why I enjoyed it, and I don't know why I'll do it again!" -BART SIMPSON