Frontal bone is a single bone because its two halves fuse very early and dont leave much trace. That joining, the metopic suture, is not nearly as visible as the saggital suture line between the two distinct parietal bones.

The top halves of the orbits (eye sockets) are part of the frontal bone which begins right at the bridge of the nose.

It touches the maxilla, the sphenoid, the temporal, and parietal bones going from bridge of nose toward the ear.