The Pedernales River is a tributary of the Colorado River, approximately 106 miles (171 km) long, in Central Texas in the United States. It drains an area of the Edwards Plateau, flowing west to east across the Texas Hill Country west of Austin. The name "Pedernales", first used in the middle 18th century, comes from a Spanish word for the flint rocks characteristic of the riverbed.

The Colorado River is an approximately 862-mile-long (1,387 km) river in the U.S. state of Texas. It is the 11th longest river in the United States and the longest river with both its source and its mouth within Texas.