Maratha Wars, (1775–82, 1803–05, 1817–18), three conflicts between the British and the Maratha confederacy, resulting in the destruction of the confederacy.
The first war (1775–82) began with British support for Raghunath Rao’s bid for the office of peshwa (chief minister) of the confederacy. The British were defeated at Wadgaon in January 1779, but they continued to fight the Marathas until the conclusion of the Treaty of Salbai (May 1782); the sole British gain was the island of Salsette adjacent to Bombay (now Mumbai)

Background:
After the death of Madhavrao Peshwa in 1772, his brother Narayanrao Peshwa ascended the position of Peshwa of the Maratha Empire. However, Raghunathrao, Narayanrao’s uncle, had his nephew assassinated in a palace conspiracy that placed Raghunathrao as the next Peshwa, although he was not a legal heir. Late Narayanrao’s widow, Gangabai, gave birth to a son after her husband’s death.
The newborn infant was named ‘Sawai’ (“One and a Quarter”) Madhavrao and legally was the next Peshwa. Twelve Maratha chiefs, led by Nana Fadnavis directed an effort to name the infant as the new Peshwa and rule under him as regents.
Raghunathrao, unwilling to give up his position of power, sought help from the British at Bombay and signed the Treaty of Surat on March 7, 1777.
According to the treaty, Raghunathrao ceded the territories of Salsette and Bassein to the British along with parts of revenues from Surat and Bharuch districts. In return, the British were to provide Raghunathrao with 2,500 soldiers. The British Calcutta Council, on the other side of India, condemned the Treaty of Surat and sent Colonel Upton to Pune to annul it. The Colonel was also sent to make a new treaty with the regency that renounced Raghunath and promised him a pension. The Bombay government rejected this and gave refuge to Raghunath. In 1777 Nana Fadnavis violated his treaty with the Calcutta Council by granting the French a port on the west coast. The British replied by sending a force towards Pune.
Second Anglo-Maratha war (1803-1805):
The war started when deposed Peshwa Baji Rao II, entered Poona with the British Forces in May 1803. British attacked from North under General Lake and from South under Arthur Wellesley, brother of the Governor General.
The fighting started from Gujarat, Bundelkhand, Orissa engaging all Maratha chiefs in their homes but not let them “reunite“. The war prolonged two years and several treaties were signed by the Maratha rulers with the Peshwa and the British.
The result of these different treaties was that the “Divided Marathas” paid the price to the “United” British.
The result of this war was as follows:
In 1803, Aurangabad and Gwalior was taken by British Bhosle lost Cuttack, Balasore and west of Wardha river Scindia lost Jaipur, Jodhpur, Gohad, Ahamad Nagar, Bharuch, Ajanta Both of Scindia and Bhosle accepted the Treaty of Bassein and gave their sovereignty to British Now the powerful Holkar was left.
He was a step ahead and approached Delhi to capture it. But he was defeated by British at Deeg, near Bharatpur, Rajasthan. At last he also signed a treaty and lost the places north of Chambal River, Bundelkhand. Poona was sure not in his claim now.
Thus with the second Anglo Maratha war, Maratha lost their independence. India was now bound in chains. The Marathas made a last attempt in 1817, unsuccessfully to get Mother India freedom from the colonist power.
Third Anglo-Maratha War (1817-19) :
The Third Anglo Maratha war consisted of skirmished such as Pindari war , Battle of Sitalbaldi, Battle of Mahidpur and Battle of Khadki. The Pinadris were many castes and classes who worked like mercenaries under the Maratha Chiefs.
When the Maratha chiefs became weak, they started raiding the territories of the British. The companies accused Marathas of giving shelter to Pinadris. Pinadris, opposed to the Marathas, who were bound by traditions of confederate government, were merely freebooters or plundering bands. They were a mix of Hindus, Muslims, Afghans, Jats and Marathas, better called as a “debris of the Mughal Empire” broken and not incorporated into any of the regimes.
The Pinadris were crushed in 1817. But in the same year three great Maratha powers at Poona, Nagpur, and Indore rose separately against the British. Peshwa Baji Rao was chafed under the terms & circumstances imposed by the Treaty of Bassein in 1802.
In June 1817, a new Treaty of Poona was signed which freed the Gaekwar from his control and ceded fresh districts to the British for the pay of the subsidiary force. The Marathas attacked the British at Khadki near Poona, and same plot was enacted at Nagpur at Sitabaldi. The Maratha armies of Indore (Holkar) rose in Mihidpur in the following month. The result was a general defeat of the Marathas.
The outcome of this war was as follows:
Dominions of the Peshwa Baji Rao were annexed to the Bombay presidency. The Peshwa surrendered, and was permitted to reside at Bithur, near Cawnpore (Now Kanpur) , on a pension of 8 Lakh Rupees per year. His adopted son Nana Sahib later led the Mutiny of 1857.
Third Anglo Maratha War 1817-19 was the last big battle won by the British. India was now theirs. The Map which was drawn by Lord Hastings remained same till Lord Dalhousie came in 1848 and imposed the infamous “Doctrine of Lapse”. The next few years were of general peace but there was a development on the foreign front.