There is a small temple or a Jeeva Samadhi for Saint Valmiki in Thiruvanmiyur, Chennai. Interestingly, Thiruvanmiyur the name of the place, itself is derived from Thiru-Valmiki-Oor. One of the 18 Siddhas of TamilNadu is Vanmeegar. Some say he is same as Valmiki who wrote Ramayana.
Maharishi Valmiki is considered as one of the main Gurus of the Valmiki(Balmiki) sect. Maharishi Valmiki Jayanthi is celebrated with fervour in most parts of north India and there are several mandirs for him in the north.
Maharishi Valmiki Temple Road Thiruvanmiyur Chennai
The Marundeeswarar Shiva temple as the name signifies, Lord Shiva is said to have blessed Sage Agastya with knowledge of medicine ( Marundu - Medicine in Tamil). Even today, the deity is worshipped by devotees for better health. Specifically, people with skin problems come to this temple on full moon days (Pournami) , light lamps and perform archana to lord Shiva.
Any large temple has a strong association with a saint. For example, Palani temple with Sidha Bhogar, Meenakshi temple with Sundarananda, Srirangam temple with Sri Ramanuja and so on. This Marundeeswarar temple is associated with Agastya and Sage Valmiki.
Another temple associated with Sage Valmiki is that of Kuchalavapureeshwarar Siva temple in Koyambedu, Chennai. It is said that the ashram of sage Valmiki was located here and the sons of Lord Rama - Kucha and Lava performed Pujas here. There is a painting in the temple which shows this incident.
Sons of Lord Rama Chennai
Another temple for Valmiki is located at Tirupathur in Sivaganga District in TamilNadu. It is said that Sage Valmiki did tapas at this place. There are several inscriptions which dot this temple,