Napa Valley provides endless opportunities for outdoor adventure. And one thing often overlooked is the Napa River, which is one of the largest rivers in the Central Coast Range, traveling 50 miles from Mt. St. Helena to San Pablo Bay. The 17 miles from the Trancas Steet bridge in Napa to Vallejo are an estuary system, with low salinity in the summer and fresh water in the winter. Here are just a few ways to explore this beautiful riparian habitat.