Yes. If you are receiving any kind of financial aid from college or government sources, you must report the scholarship to the financial aid office.
Unfortunately, the college will adjust your financial aid package to compensate. Nevertheless, the outside scholarship will have some beneficial effects. At some colleges outside scholarships are used to reduce the self-help level. For example, at MIT the outside scholarship is first applied to reducing the self-help level, and only when the scholarship exceeds self-help does it replace institutional grants. At other colleges outside scholarships are used to replace loans instead of grants.