The states came within the British sphere of influence after the Second Anglo-Maratha War of 1803–1805. In 1811, when the Maratha power was declining, the British Government stipulated to collect and pay over to the ruler of Baroda the yearly tribute of the Mahi Kantha states. In 1820 they finally took over the management of the whole territory, agreeing to collect and pay over the tribute free of expense to Baroda, while Baroda was pledged not to send troops into the country, or in any way to interfere with the administration. After a few disturbances in the 1830s, in 1857-8 and 1867, peace remained unbroken in the region until 1881, when the Bhils of Pol rose against their chief and extorted from him a settlement of their claims.
The famine of 1899–1900 was severely felt in Mahi Kantha, and the population of the agency decreased by 38% in the decade 1891–1901 due to famine. Many of the inhabitants were Bhils and Kolis. In 1897 a metre-gauge railway was opened from Ahmedabad through
Parantij near Ambliara State to Ahmednagar. At
Sadra was the
Scott College for the education of the sons of rulers on the lines of a British public school. There were also English language schools at Sadra, Idar and Mansa.