Check with the local fire department or hospital. There is a "Safe Baby" law that you can drop your baby off, get a wrist band of identification, and without question leave the baby for adoption within the first 30 days of life.
After that, you can place your child for adoption with any agency. You will have to sign termination of parental rights papers. You will probably have to have at least one counseling session.
There are also organizations to help you keep your child.