What California highway is the longest in the state and is associated with the Ventura River?
Ventura River:  In its final stretch, the Ventura River flows through the Ventura River estuary, which extends from about the 101 Freeway bridge to the Pacific Ocean. U.S. Route 101 in California: U.S. Route 101 (US 101) in the state of California is one of the last remaining and longest U.S. Routes still active in the state, and the longest highway of any kind in California.
U.S. Route 101