The Adoni fort is central to the town's history. In 1780, an observer wrote,
"Adoni is situated upon three mountains which are united; it has a range of irregular fortifications, piled one over the other. To maintain it requires a garrison of 30,000 men. The fortifications upon the mountains are often weak...To the south of Adoni, a large plain, to the north there are mountains, obnoxious from their nearness, to the east there are other mountains. To the west there are also mountains and this part is the weakest."
In the 15th century and early to mid 16th century, Adoni was a fort town of the Vijayanagara Empire. It was held by the kinsmen of Aliya Rama Raya, a powerful aristocrat of the Vijayanagara.
From approximately 1558, at the decline of the Vijayanagara Empire, control of Adoni came to Ali Adil Shah I (1558–1579), the fifth Sultan of the Bijapur Sultanate. Hamilton, in 1820, stated,
"It [Adoni at this time] stood at the top of a high hill, and contained within its walls many tanks and fountains of pure water with numerous princely structures."
In 1564, the Sultanate of Bijapur lost Adoni to Mohammedan rulers.
From 1678 to 1688, rule of Adoni lay with Siddi Masud, a wealthy Habshi (African) from Abyssinia who was a powerful general of Raja Anup Singh of Bikaner, Siddi Masud improved the fort; cleared the surrounding forest; established the townships of Imatiazgadh and Adilabad; and constructed the Jamia Masjid. Siddi Masud was also an avid art collector and a patron of the Kurnool school of painting. In 1688, Adoni was attacked by Firuz Jang, a Mughal general. Siddi Musud surrendered with his courtiers and family.
At the fall of the Mughal Empire, around 1760, Adoni was ruled by governors appointed by the Nizam of Hyderabad, a Mughal splinter clan. One such governor was Salabat Jung, brother of the Nizam. The French supported the appointment. However,
"Salabat Jung was very mild by disposition and neither Bussy nor Dupleix rated his intelligence highly. In fact, Dupleix went to the extent of calling him a duffer
In 1786, Adoni was besieged for one month and then captured by Tipu Sultan of the Kingdom of Mysore of South India. On 4 May 1799, Tipu Sultan died at the hands of the English. On the 15 June 1800, Arthur Wellesley, Marquess of Wellington, wrote to the resident at Hyderabad about appropriate reparations to the Nizam for English occupation of Adoni which he felt was a desirable location. Adoni became one of twenty taluqs and in 1810, the Adoni and Nagaldinna taluqs were combined. In Adoni in 1817, at the beginning of the Third Anglo-Maratha War, the British raised a new battalion from other nearby regiments. By 1842, the military had left Adoni because of the perception that the area was susceptible to cholera and because of unfavourable rugged surrounding geography. Under British rule, South India was divided into several administrative districts. Adoni fell into the district of Bellary of Madras presidency. On 29 April 1861, the acting district engineer of Kurnool wrote to the chief secretary to government at Fort St George,
"North and by east of Bellary, on the Hyderabad road, the only important town is Adoni; it contains a very large population of Mussulmen, and is a place of considerable trade and manufacture."
In 1867, the Adoni and the Bellary Municipal Councils were created. Between 1876 and 1878, a severe El Nino famine affected Adoni and the surrounding areas where nearly one third of the population was lost. In 1953, after the linguistic reorganization of the states, Adoni gained its present seat as part of Andhra Pradesh.
Adoni is located at 15.63°N 77.28°E / 15.63; 77.28. It has an average elevation of 435 metres (1427 feet) above sea level. The climate is mainly tropical, with temperatures from 31 °C to 45 °C in summer and 21 °C to 29 °C in winter. The soil is black and red. There are large limestone deposits suitable for cement. There are a number of minerals such as copper, lead, zinc and in some places, diamonds.
As of 2011 the Census of India, recorded in the town a population of 166,537. The total population constituted 82,743 males and 83,794 females. These numbers produced a gender ratio of 1013 females per 1000 males, which was higher than the national average of 940 per 1000. In the same year, 18,406 children were between 0 and 6 years of age. In this group, 9,355 were boys and 9,051 were girls, giving a gender ratio of 968 per 1000. The average literacy rate was 68.38 percent with 101,292 literate people. This number was significantly lower than the national average of 73 percent.
The urban agglomeration had a population of 184,771, of which 92,006 were male and 92,765 were female, giving a gender ratio of 1008 females per 1000 males. Children aged 0 to 6 years numbered 20,517. There were 112,151 literate people giving an average literacy rate of 68.28 percent.
Adoni is a large producer of cotton and has a substantial ginning and textile industry. Second in importance is groundnut oil. Adoni is an important trading centre in Andhra Pradesh with a big market situated in the centre of the town.
Historical Adoni Fort and Shahi Jamia Masjid built in 1660 by Siddi Masud are some of the notable landmarks around the city.
APSRTC operates buses from Adoni bus station.
Adoni railway station and its connections were built during British rule in 1870. It is now a part of the South Central Railway on the Solapur-Guntakal line which is part of Chennai-Mumbai line.
The primary and secondary school education is imparted by government, aided and private schools, under the School Education Department of the state. The medium of instruction followed by different schools are English, Telugu.
Adoni Arts and science college Government Polytechnic, and TGL Gopalsetty Polytechnic are major colleges.