Northwest Pennsylvania is home to 10 turtle species of, 18 snake species, and two lizard species. Ten species of turtles and eight species of snakes have been recorded from Presque Isle. Presque Isle has an especially abundant turtle fauna. Most turtles are at least partially aquatic, but wood turtles and box turtles spend a large part of their time on land. The largest turtle in the region is the common snapping turtle, which averages 35 cm (14 in) in carapace (upper shell) length. The smallest turtle in the region was the bog turtle (adults averaging under 10 cm or 4 in), but this species has been extirpated from the region since the early 1900s. The common map turtle may be seen basking by the hundreds on logs in the park on sunny summer days. Presque Isle is the type locality for this species, which means that it was originally described from a specimen collected at the park. The rare Blanding's turtle is found nowhere else in Pennsylvania except Presque Isle.
Eighteen snake species have been recorded from northwest Pennsylvania, including all three of Pennsylvania's venomous snakes (timber rattlesnake, massasauga rattlesnake, and northern copperhead). Snakes in the region can be found streams, ponds, wetlands, fields, and forests, depending on the habitat preferences of the species. The majority of the entire range of shorthead garter snakes and mountain earth snakes is within Pennsylvania. Eight species of snakes have been recorded on Presque Isle.