Kanchipuram sits at the junction of several worthwhile day trips, all within 2 hours.
Chennai (75 km, ~1.5 hours) is the natural base for visiting Kanchipuram, and the traffic flows in the right direction — leaving Chennai early avoids the worst congestion. The return journey makes a good afternoon city visit: the Government Museum on Pantheon Road has one of India's better collections of Pallava and Chola bronzes, which puts Kanchipuram's temples in art-historical context.
Mahabalipuram (Mamallapuram, ~60 km from Kanchipuram via the East Coast Road, ~1.5 hours) is another Pallava site — the dynasty's port city — with the famous Shore Temple on the beach, the Five Rathas carved from single boulders, and the vast Arjuna's Penance relief. The two sites together constitute the most complete picture of Pallava architecture available; visiting both in the same trip is logical.
Tiruvannamalai (~100 km southwest, ~2 hours) is one of the great Shaiva pilgrimage centres of Tamil Nadu, built around the sacred hill Arunachala, which is identified with Shiva himself. The Arunachaleswarar Temple at the base is one of the largest temple complexes in India. Sri Ramana Maharshi spent most of his life here, and the ashram is still a functioning spiritual centre. The contrast with Kanchipuram — from Pallava archaeology to living pilgrimage tradition — is striking.
