A geologist's tour of Arizona's San Pedro River

The San Pedro River is Arizona's last undammed river. AZGS geologist Joe Cook and his colleagues  recently mapped the extent of Holocene channel and floodplain alluvium there. Our online interactive map tour takes us on a 122-mile trek from the US-Mexico border to Winkelman, Arizona, to show you the San Pedro River Valley as seen through the eyes of a geologist.