Mahishmati (IAST: Māhiṣmatī) was an ancient city in present-day central India. It was located in present-day Madhya Pradesh, on the banks of Narmada River, although its exact location is uncertain. This ancient city was the capital was Haihaya dynasty which ruler Mahishmant got in boon from Mahesh for only Haihayavanshi rulers. According to the boon, after the end of the rule of Haihayas on Mahishmati, this city ended and turned into Maheshwar. The city may have flourished as late as until 13th century, as indicated by a Paramara inscription.
The most famous Haihaya Emperor from Mahishmati was Kartavirya Arjuna which is mentioned in Vedas too. After Kartavirya, This city was ruled by his several Haihaya descend branches like the Vitihotra or Talanjangha, Avanti, Kalachuri and Vrṣhni or Chandel dynasties. Mahishmati was the most important city in the southern part of the Avanti kingdom. The Avanti Kshatriyas of Haihaya branch later served as feaudal of the Anupa Kingdom of Daksha line during Mahabharat.
The following things are known about Mahishmati's location:
Several cities in Madhya Pradesh, located along the Narmada river, are claimed to be the ancient Mahishmati. These include:
The Sanskrit epic Ramayana mentions the attack of Rakshasa king Ravana on Mahishmati. The Anushasana Parva states that Ikshvaku's son Dashashva was a king of Mahishmati. It goes on to mention that the Haihaya king Kartavirya Arjuna ruled the entire earth from his capital Mahishmati (13:52). He was killed by Bhargava Rama.
Mahabharata mentions Mahishmati as part of a kingdom distinct from the Avanti kingdom. The Sabha Parva (2:30) states that the Pandava general Sahadeva attacked Mahishmati, and defeated its ruler Nila. Mahismati was protected by Agni, due to his matrimonial relationship with the king's daughter. Agni even granted the unmarried women of Mahismati liberty of not staying with only one husband forever, and moving about freely.  King Nila of Mahishmati is mentioned as a leader in the Kurukshetra War, rated by Bhishma as a Rathi. His coat of mail had blue colour (Mbh 5:19,167).
Harivamsha (33.1847) names the founder of Mahishmati as Mahishmant, a king who was the son of Sahanja and a descendant of Yadu through Haihaya. At another place, it names the city's founder as Muchukunda, an ancestor of Rama. It states that he built the cities of Mahishmati and Purika in the Rksha mountains.
The Raghuvamsa states that Mahishmati was located on the Reva river (Narmada), and was the capital of the Anupa country.
Another account states that Kartavirya Arjuna conquered Mahishmati city from Karkotaka Naga, a Naga chief and made it his fortress-capital.
The Buddhist text Digha Nikaya mentions Mahishmati as the capital of Avanti, while Anguttara Nikaya states that Ujjaini was Avanti's capital. The Maha-Govinda Suttanta also states that Mahishmati as the capital of Avanti, whose king was one Vessabhu. It is possible that the capital of Avanti was transferred from Ujjayani to Mahishmati temporarily.
The Dipavamsa mentions a territory called Mahisa, describing it as Mahisa-ratta ("Mahisa country"). The Mahavamsa describes this region as a mandala, calling it Mahisha-mandala. The 5th century Buddhist scholar Buddhaghosa terms this territory variously as Rattham-Mahisham, Mahishaka-mandala and Mahishmaka. John Faithfull Fleet theorized that Mahishmati was the capital of this region, which was named after a tribe called "Mahisha". This appears to be same as "Mahishaka", which is described as a southern kingdom (that is, south of the Vindhyas and the Narmada) in the Bhishma Parva of the Mahabharata.
The Sutta Nipata states that when Bavari's disciples traveled from Pratishthana to Ujjayani, Mahishmati was one of the cities on the route. The inscriptions at Sanchi mention that pilgrims from Mahishmati visited the stupa at Sanchi.
During the 6th and 7th centuries, Mahishmati may have served as the capital of the Kalachuri Kingdom.
Rulers of some 11th and 12th century kingdoms in present-day South India claimed Haihaya ancestry. They indicated their claimed place of origin with the title "Lord of Mahishmati, the best of the towns".
Mahishmati appears to have been a flourishing city in as late as the 13th century. A 1225 CE inscription of the Paramara king Devapala mentions that he stayed at Mahishmati.
The Baahubali film series is set in a fictionalized version of the kingdom.