National Highway 166E, commonly referred to as NH 166E is a national highway in India. It is a spur road of National Highway 66. NH-166E traverses the states of Maharashtra and Karnataka in India.
Guhagar, Chiplun, Patan, Karad, Kadegaon, Vita, Khanapur, Nagaj, Jat, Bijapur.
Post declaration of this route as national highway, construction process to upgrade the road to national highway standards started in 2017. Larsen & Toubro was awarded the contract to upgrade 48.4 km section from Helwak to Karad.