Are there different admissions requirements for different departments or majors?

Most schools have general requirements for admission, that are not major or department-specific. You can contact the universities you are interested in for admissions requirements (ie math, foreign language, test scores, etc). If you know the field you want, that may help you narrow your search. Sometimes if a school has an impacted program (large numbers of applicants) they will specify other courses or subjects that are required or would be helpful, as well.