Puerco Ruin and Petroglyphs, Archaeological site in Petrified Forest National Park, Arizona, US.

Puerco Ruin is an archaeological site featuring sandstone block structures with roughly 100 rooms arranged around a central plaza. The surrounding boulders display more than 800 petroglyphs carved into the rock surfaces.

The site was occupied in two periods of about a century each, from 1100 to 1200 and from 1300 to 1400, with the larger second occupation in the 1300s. Ancestral Puebloans farmed corn, beans and squash on the Puerco River flood plain and traded with the Hopi and Mogollon. After droughts and later climatic changes, the pueblo was deserted by 1380.

The name Puerco comes from the Spanish word for pig, given to the river by early Spanish explorers. The Ancestral Puebloans grew corn, beans, and squash on the Puerco River floodplain and made baskets and painted pottery. The river also served as a trade route, and the residents had contact with the Hopi to the west and the Mogollon to the south.

A paved loop trail guides visitors through the ruins starting from Petrified Forest Road, located roughly 10 miles (16 km) from the north entrance. The entire path is wheelchair accessible for all visitors.

The petroglyphs show bears in 21% of the carvings and birds in 16%, although excavated animal remains from the pueblo are over 90% small mammals such as rabbits and prairie dogs, with no bear bones at all. The rock art therefore records animals the residents rarely hunted or ate.