National Highway 66 connects the Union Territory of Pondicherry
, at the junction of national highways 7
, in Tamil Nadu
. National Highway 66 starts at Pondy and runs north-west up to Tindivanam
, the distance traveled being 39 km. It then turns westwards and passes past Gingee and Thiruvannamalai
, turns north-west and then beyond
to eventually terminate at Krishnagiri. National Highway 66 is 10 km long in Pondicherry while the rest of its 234 km is in Tamil Nadu.