My father had a son with a woman a year before I was born. I'd like to know how to find my older brother if there is a way. I am seventeen and just found out about the whole thing. I live in South Carolina. Is there a way to find my brother?

If you are trying to do this without parental permission, you can't until you are 18.

Remember also that the "brother" may not even know you exist, his mother may not know you exist. Consider how many lives you may be disrupting.

I find it very hard to believe that only 18 years ago the adoption was completely closed.

You need to talk to your dad, and HE is the one that can initiate a search... not you. As a minor, you have no way of conducting the search legally, and as ONLY a biological sibling, your rights to search fall behind the rights of BOTH of his biological parents and your biological brother.

I suggest you talk to your dad and forget about searching yourself right now.

How to proceed might also depend on how OP found this out...