The remaining district, with Vellore as its headquarters,[2] passed intact into the Madras State of independent India.

Historically, the name "Arcot" is said to be derived from a linguistic corruption of the original Tamil word "Aaru Kaadu", meaning "Six Forests".

On the north the district is separated from Cuddapah by a portion of the Eastern Ghats and locally known as the Tirupati Hills, form the town of that name which lies at their foot.

In the south-west, separated from the eastern ghats by the fertile valley of the Palar, is the detached group of the Javadi Hills, well wooded and containing much game which divides the district from Salem and part of South Arcot.

Along the southern and eastern borders, adjoining South Arcot and Chingleput, the terrain is flat and uninspiring.

From all the hill ranges, numerous small boulder-covered spurs branch off towards the center of the district and combine to render it one of the most varied and picturesque areas in the region.