Jammu is the winter capital of the Indian union territory of Jammu and Kashmir. It is the headquarters and the largest city in Jammu district of the union territory. Lying on the banks of the river Tawi, the city of Jammu, with an area of 26.64 km2 (10.29 sq mi), is surrounded by the Himalayas in the north and the northern-plains in the south. Jammu is the second most populous city of the union territory. Known as the City of Temples for its ancient temples and Hindu shrines, Jammu is the most visited place in the union territory. Jammu city shares its borders with the neighbouring Samba district.
The city spreads around the Tawi river with the old city overlooking it from the north (right bank) while the new neighbourhoods spread around the southern side (left bank) of the river. There are five bridges on the river. The city is built on a series of ridges
According to Tarikh-i-Azmi, Jammu came into existence around 900 CE. The state of Durgara (modern forms "Duggar" and "Dogra)") is also attested from around this time.The capital of the Durgara state at that time is believed to have been Vallapura (identified with modern Billawar). Its rulers are repeatedly mentioned in Kalhana's Rajatarangini. Babbapura (modern Babor) is another state mentioned in Rajatarangini, some of whose rulers occur in the Vamshavali (family chronicles) of later Jammu rulers. These rulers are believed to have enjoyed almost independent status and allied themselves with the Sultans of Delhi. Raja Bhim Dev is prominently mentioned in the Delhi chronicles as a supporter of Mubarah Shah (r. 1421–1434)
Jammu is mentioned by name in the chronicles of Timur (r. 1370–1406), who invaded Delhi in 1398 and returned to Samarkand via Jammu. In the Mughal chronicles of Babur in the early 16th century, Jammu is mentioned as a powerful state in the Punjab hills. It is said to have been ruled by Manhas Rajputs. Emperor Akbar brought the hill kingdoms of the region under Mughal suzerainty, but the kings enjoyed considerable political autonomy. In addition to Jammu, other kingdoms of the region such as Kishtwar and Rajauri were also prominently mentioned. It is evident that the Mughal empire treated these hill chiefs as allies and partners in the empire.