National Highway 46 was a national highway in the Indian state of Tamil Nadu. It ran from Krishnagiri to Walajapet in the state. It passed through Vellore and it was a highly important connecting road for vehicles travelling between Chennai and Bangalore. The total Length of NH 46 was . The Krishnagiri-Walajapet section is being upgraded to six lanes by L&T on a build-operate-transfer basis.
Old national highway 46 has been renumbered as National Highway 48, which runs from Delhi to Chennai via Mumbai and Bangalore.
Krishnagiri, Bargur, Nattrampalli, Vaniyambadi, Ambur, Pallikonda, Vellore, Arcot, Ranipet and Walajapet.