The most ancient temples in India are as below:-
(all imges used are credited to Instagram)
Kashi Vishwanath Mandir (Varanasi UP)
Kashi Vishwanath Temple is dedicated to MahaShiva. It is located Varanasi, Uttar Pradesh, India. The temple is one of the twelve Jyotirlinga shrines. The presiding deity is known by the names Vishwanath and Vishweshwara, meaning Lord of the Universe.
Mundeshwari Devi Mandir (Kaimur Bihar)
It is an ancient temple which is believed to be dedicated to the worship of the goddess Durga and MahaShiva, and is claimed as the oldest functional Hindu temple in the world.
Somnath Mandir (Patan Gujarat)
Somnath Temple is located in Patan Gujarat, India. It is one of the first among the twelve jyotirlinga shrines of MahaShiva.
Kailasa Temple (Sambhaji Nagar MAHARASHTRA)
Kailasa temple dedicated to MahShiva built by Rashtrakuta Rulers in 8th Century. Kailasha or Kailasha-natha temple is the largest of the rock-cut Hindu temples at the Ellora Caves in Sambhaji Nagar district of Maharashtra, India.
Brihadeeswara Mandir (Thanjavur TN)
Brihadeeswara Mandir also called Rajarajesvaram temple by the name of king Raja Raja chola who built it a Shaivite Hindu temple in a Chola architectural style located on the south bank of the Cauvery river in Thanjavur, Tamil Nadu, India.
Adi Kumbeshwar Mandir (Kumbakonam TN)
This temple is dedicated to MahaShiva it built by Chola rulers.
Jagannath Puri Mandir (Puri Odisha)
The Jagannath Temple is dedicated to the god Jagannath, a form of Vishnu. It is located in Puri in the state of Odisha, situated on the eastern coast of India.
Konark Surya Mandir
Konark surya Mandir is built by king Narsimhadeva of East Ganga dynasty in 13th Century. Konark Sun Temple is a 13th-century UNESCO World Heritage Site located in Konark, Odisha, India, built to resemble the chariot of the Sun God Surya, featuring 24 elaborately decorated wheels and led by horses.