Present day Pratapgarh is known as Kanthal Nagari since from principality era. Pratapgarh principality (present day Pratapgarh Town) was eastablished in the year 1699 by Maharawat Pratapsingh. In the 14th century, Maharana Kumbha (1433–1468) ruled Chittorgarh. Due to a dispute with his younger brother Kshemkarn (1437–1473), he expelled him from his territory. Kshemkarn's family was a refugee for some time and lived in the Aravali ranges in the southernmost part of Mewar regime. In 1514, Kshemkarn’s son Prince Surajmal (1473–1530) became the ruler of Devalia (Devgarh), and this principality later came to be known as Pratapgarh principality. Prince Surajmal established his capital of 'Kanthal-Desh' at Dewaliya (also called Devgarh), a small town about 10 km in the west from present Pratapgarh town, where old temples, cenotaphs, a historical palace and other ruins of bygone Partapgarh regime still can be seen. Thus, historically, Pratapgarh has been an integral part of Mewar Rulers of Udaipur. 

As the climate of Devgarh was not found to be suitable by the royal family, one of the descendants of Surajmal, Maharawat Pratapsingh of 10th generation (1673–1708) started to build a new town near native village Devgarh in 1689–1699 and later named it as Pratapgarh, with a fort wall around his new palace and small township with eight entry gates. At that time, the area of Pratapgarh was reported to be about 889 square miles, whereas Dhariyawad, another small town near Pratapgarh, was founded by Rana Sahasmal, the grandson of legendary Maharana Pratap in the mid-15th century. 

The name of Pratapgarh is after Maharawat Pratap Singh and not Maharana Pratap, as commonly mistaken. 

Sisodia clan is amongst the ancient royal families in India. This family ruled Mewar for more than eight hundred years. The famous Rajputs- Maharana Sangram Singh (also known as Rana Sanga), Maharana Kumbha and Maharana Pratap all belonged to this family. The rulers of 'Partapgarh' principality were descendants of Sisodia clan of Mewar Rajputs.

The successive rulers of Pratapgarh after Kshemkarna (1437–1473) were Soorajmal (1473–1530) Bagh Singh (1530–1535), Rai Singh (1535–1552), Vikram Singh (1552–1563), Tej Singh (1563–1593), Bhanu Singh (1593–1597), Singha (1597–1628), Jaswant Singh (1628) Hari Singh (1628–1673), Maharawat Pratap Singh (1673–1708), Prithvi Singh (1708–1718), Sangram Singh (1718–1719), Ummed Singh (1719–1721), Gopal Singh (1721–1756), Saalim Singh (1756–1774), Saamant Singh (1774–1844), Dalpat singh (1844–1864), Uday Singh (1864–1890), Raghunath Singh (1890–1929), Sir Ram Singh (1929–1940) and Ambika Pratap Singh (1940–1948) who lived in Pune after leaving his native place.

Just after the independence of India in 1947, a princely state of Pratapgarh accepted the offer of then Home Minister Sardar Vallabh Bhai Patel to join Indian State on a condition that Pratapgarh must be declared as a newly independent district in Rajasthan. Pratapgarh remained as an independent district between 1948-1952, however, due to the reconstitution of district boundaries, Pratapgarh became part of the Nimbahera district and then of Chittorgarh.

After a long struggle of 56 years, Pratapgarh got the honour of being a district. On 26th January, 2008 Smt. Vasundhara Raje, the Chief Minister of Rajasthan, then announced Pratapgarh to be a 33rd independent district of Rajasthan.