From Chennai, take the Poonamallee High Road and then on, take the Chennai- Bangalore Highway and continue on passing thro Vellore and Ambur till you reach Ponneri junction where there is a sign board pointing towards Yelagiri.
From Bangalore, get on the Hosur toad (NH7) and head towards Krishnagiri. Drive on NH46 till you see a sign that takes you to Yelagiri.
If you plan on travelling by the train, the nearest station would be Jolarpet. Cabs and buses are available from here.