外沢隧道は、長野県北安曇郡小谷村の国道148号旧道にある隧道。外沢トンネル開通によって廃道となった区間にある。この区間全域に渡って崩落が激しい。
Tsunesawa is a tunnel located in the old road of Route 148, Otari village in Kitaazumi District, Nagano Prefecture. It is in the section which became a waste road by the opening of the Yuzawa tunnel. Collapse is intense throughout this section.