Ratangarh is a town in the Churu district in Rajasthan, India. Ratangarh was previously called Kolasar. It is famous for grand havelis (mansions) with frescoes, which is an architectural speciality of the Shekhawati region. Ratangarh is also famous for its handicraft work.There are so many temples in Ratangarh that it has earned the nickname "the Varanasi of Rajasthan". Salasar Balaji, the most famous and widely popular religious spot in the District is situated 45 Kms south-east of Ratangarh .
The Raja of Bikaner, Ratan Singh, built a massive fort at Ratangarh in 1820 AD. The market place of the town is in the shape of a cross suggesting that the city was planned before construction. An array of stately havelis line the main crossing, which is also graced by a Clock Tower. The town is the site of a major power station, supplying electricity is supplied from Ratangarh up to Jaipur.
According to historical documents Ratangarh was founded by Surat Singh, the maharaja of Bikaner in the year 1798 (Samvat 1855) while he was returning from Churu with his son Ratan Singh. He selected the place Kolasar and Rajia ki dani for a new town and named it Ratangarh on his son's name. He handed over the responsibility to Purohit Hulashchand, Deepchand and Charan Siddai Shankar to build Ratangarh as a modern 1812 (Samvat 1869) during the layout of Ratangarh. According to some old people present Ratangarh was build at Kolasar village, and Asha Charni (Lado Bhuwa) constructed Raghunathji temple.