Ajmer is significant for the Urs of Ajmer Sharif:

'Dargah Sharif' or 'Holy Dargah' is one of the most sacred Muslim shrines in the country. Venerated by both Hindus and Muslims, Ajmer Sharif is the tomb of Khwaja Moin-ud-din Chisti, a Sufi saint who came from Persia and devoted his life to the service and upliftment of the poor and downtrodden. The ajmer dargah has a massive gate with silver doors built in several stages. Revered by the Mughal rulers, it has touches of Humayun to Shah Jahan in its structural architecture. A silver railing and a marble screen surround the actual tomb of the saint, made of marble with a gold plated dome.

Ajmer city is one of famous city of Rajasthan. Ajmer is significant for the Urs of Ajmer Sharif, which is held in the memory of the honored Sufi Saint Khawaja Moinuddin Chisti, it is an time for thousands of believers to assembled at the shrine and offer their prayers. All of Ajmer seems to take on a festive air and several programmes are organised to mark the Festival.

Ajmer finds its name on the international map mainly because of the highly esteemed Dargah of Khwaja Moin-ud-din Chisti. The Ajmer Dargah is situated at the base of a desolate hill in the city of Ajmer and is entered after crossing through the Dargah Bazaar. Though it is basically a Muslim shrine, yet follower of all religions have tremendous faith in its genuineness.

The History of Rajasthan to the Hindu Methology and the Rajput of Rajasthan:

According to the Hindu Mythology, the Rajputs of Rajasthan were the descendants of the Kshatriyas or warriors of Vedic India. The emergence of the Rajput warrior clans was in the 6th and 7th centuries. Rajputs ancestry can be divided into two: the "solar" or suryavanshi-those descended from Rama, the hero of the epic Ramayana, and the "lunar" or chandravanshi, who claimed descent from Krishana, the hero of the epic Mahabharata. Later a third clan was added, the agnikula or fire-born, said to have emerged from the flames of a sacrificial fire on Mt Abu.
Early History

Rajasthan is the north-western region of India, and has remain independent from the great empires. Buddhism failed to make substantial inroad here; the Mauryan empire (321-184 BC), whose most renowned emperor, Ashoka, Converted to Buddhism in 261 BC, had minimal impact in Rajasthan, However, there are Buddhist caves and stupas (Buddhist Shrines) at Jhalawar, in Southern Rajasthan.

Ancient Hindu scriptural epics make reference to sites in present-day Rajasthan. The Holy Pilgrimage site of Pushkar is mentioned in both the Mahabharata and Ramayana.
Source: http://www.indianaturetourandtravels.com