The moth looked a little tattered and was sluggish, as these giant silkworm moths tend to be. With these species' it is all about the caterpillars. The adults do not feed, rather they spend their week or less of life, mating and laying eggs.
This one looks like a female. Males have much bushier antennae, which they use to smell female pheromones.
I moved the moth to the shady lawn at the edge of the woods. There it spread its wings, displaying a beautiful set of "eyespots" on the hind wings. The moth will flash these owl-like "eyes" to scare potential predators. The dead leaf look when the wings are closed offers more protection, hence my initial thought that it was a pile of leaves on the driveway.
Polyphemus moth, Antheraea polyphemus
Although a "silkworm" moth, along with the well-known luna moth and cecropia moth among others, these American silkworm moths are not the source of silk. Attempts at harvesting silk commercially from these moths has apparently failed. Silk for textiles comes from the Silkmoth, a member of a related but different family. Regardless, all the silkworm moths are gorgeous - keep an eye out for these giants.