The Napa River, approximately 50 mi (80 km) long, is a river in northern California in the United States. It drains a famous wine-growing region called the Napa Valley in the mountains northeast of San Francisco.

It rises in northwestern Napa County south of Mt. St. Helena in the Mayacamas Mountains of the California Coast Ranges. It flows south for 4 mi (6 km), entering the head of the slender Napa Valley north of Calistoga. In the valley it flows southeast past Calistoga and Napa, its head of navigation. Downstream from Napa it forms a tidal estuary, entering Mare Island Strait , a narrow channel on the north end of San Pablo Bay. Its watershed encompasses approximately 426 sq mi (1120 km²).

Best known for the vineyards in its valley, the river also provides a habitat for salmon and steelhead. Although chinook salmon still spawn in the river, the Coho salmon population is extinct in the river and the steelhead population has been greatly reduced in recent years.

External links

• Napa River Watershed
• UCSB: Napa Watershed