What kind of snake?
Thank you for your question. The snake in your photograph is a Northern Brown Snake (Storeria dekayi dekayi). It is non-venomous.
This species is common throughout most of the eastern half of the United States. The snake in your photograph is an adult. Their coloration can vary from individual to individual. Yours is the typical color and pattern, but some individuals are dark gray, some are lighter colored than your specimen and some are more reddish. Typical length for this species is a little less than 12 inches. Maximum length is approximately 20 inches. They spend most of their time under mulch, pine straw, leaf litter, etc. searching for their primary food, earthworms and slugs. They will also eat snails (they pull the snails out of their shells first), various insects, very small salamanders and spiders.
If threatened, they will usually attempt to escape first. If that fails, they may play dead, attempt to conceal their head beneath their coils or flatten their body to make themselves appear larger than they really are. If handled, they may release a strong-smelling musk from their anal glands, but usually calm down pretty quickly. They generally do not attempt to bite.
We usually get several calls a year on this species as people are out working in their gardens and replacing old mulch or pine straw, and they uncover them while raking.
Here's a link to the PA Herp webpage for this species:
Here is an excellent field guide that cover snake species found in Pennsylvania:
Gibbons, W. (2017). Snakes of the Eastern United States. Athens: The University of Georgia Press.