A sizeable number of Kammas have emigrated to the United States.
The community of Kammas is thought to be that of agricultural families originating from the Kammanadu region of the Guntur and Prakasam districts in Andhra Pradesh.
The tradition holds that the Kammas, along with Velamas and Reddis, evolved out of the community of Kapus (cultivators) in the post-Kakatiya period. A popular legend collected by Edgar Thurston narrates that Kammas originated from the youngest son of a certain Belthi Reddi, who managed to recover his mother's ear-ornament (called "kamma" in Telugu) which had been appropriated by a king's minister. The other sons of Belthi Reddi are similarly said to have given rise to the other prominent caste communities of the Telugu people.
During the reign of Krishnadevaraya Kammas belonging to 37 gotras were living in the city of Vijayanagar. Kamma Nayaks formed the bulwark of the Vijayanagara army and were appointed as governors in many areas of Tamil Nadu.Pemmasani Ramalinga Nayudu was the chief military commander under Krishnadevaraya. Their role in protecting the last great Hindu kingdom of India was significant.
The Kammas were largely reduced by the status of peasants in the post-Kakatiya period. The Vijayanagara kingdom was troubled after the battle of Tallikota in 1565. Pemmasani Nayaks, Ravella Nayaks and Sayapaneni Nayaks helped the Araviti kings in keeping the Muslims at bay. It took another 90 years to consolidate the Muslim power in Andhra country with the capture of Gandikota in 1652. Kamma nayaks migrated in large numbers to the Tamil region. During the Golkonda period, the Sayapaneni Nayaks (1626-1802) ruled Dupadu region as vassals of the Golkonda sultans.
Kamma landholdings were consolidated, and their influence consequently increased, by the introduction of the ryotwari system as a replacement for the zamindari system in the 19th century.
In the 1872 census, the Kammas made up 40 per cent of the agricultural population of the Krishna district (which included the present Guntur district until 1904). Along with Brahmins, they formed the domininant community of the district. By 1921, their population in the district increased to 47 per cent, representing a large in-migration. The literate Kammas learned the Vedas, wore the sacred threads, taught Sanskrit and performed priestly functions for the lower-caste members, which are said to have generated controversies. Despite this attachment to Brahminical orthodoxy, the Kammas related to the Kapus (cultivators) and their Shudra identity. The upward mobility of the community was noted in N. G. Ranga's study in the 1920s. The Kammas were also politically active, associating themselves with the Indian National Congress almost from its inception, and agitated for farmers' interests. They formed the Kamma Mahajana Sabha, a caste association, in 1910, which received encouragement from the political leaders. Ranga also started a Madras Kamma Association in 1919 and founded a journal Kamma Patrika, later renamed to Ryot Patrika. The Kammas constituted 6 per cent of the population in the Telugu-speaking of the Madras Presidency in 1921, a figure slightly higher than Brahmins, but lagging far behind 'Kapur or Reddi'.
Construction of dams and barrages and establishment of an irrigation system in Godavari and Krishna River deltas by Arthur Cotton was a great boon to the Kamma farmers. Availability of water and the natural propensity for hard work made the Kammas wealthy and prosperous. The money was put to good use by establishing numerous schools and libraries and encouraging their children to take up modern education.
The Kammas of Southern Tamil Nadu have also excelled in the cultivation of black cotton soils and later diversified into various industrial enterprises, particularly in Coimbatore and Kovilpatti.
The varna system of Brahmanic ritual ranking never took hold in South Indian society outside Kerala. There were essentially three classes: Brahmin, non-Brahmin and Dalit. Kammas naturally fall into the non-Brahmin class Classification of social groups in the Andhra region has changed frequently as the various communities jostle for status. During the British Raj, the Kammas were considered to be "upper Shudra", along with the Reddy and Velama castes, under the varna system.
Kamma lore nurtures the image of a once-proud warrior clan reduced by Reddi chicanery to its present peasant status. Reddi duplicity, recounted by Kamma historian K. Bhavaiah Choudary, was first apparent in 1323 AD at the downfall of Andhra's Kakatiya dynasty. Reciting voluminous records to prove that Kammas dominated the Kakatiya court, Chaudary suggests that the Reddis, also influential militarists at the time, struck a deal at Kamma expense with the Moslem conquerors of the Kakatiya regime. The Kammas lost their noble rank and were forced into farming.
Prior to the bifurcation of Andhra Pradesh, creating the new state of Telangana, the Kammas and the Reddys were politically and economically dominant in the state.
^N?gabha?a?arma, M.; Sastry, M. V.; agirir?vu, C. (1995), History and culture of the Andhras, Telugu University, p. 80 Quote: "Next to birth and profession, it was region which accounted for sectarian sub-divisions in all the castes like those of Kammanadu being called Kamma-Brahmana, Kamma-Kapu, Kamma-Sresthi and so on."
^Sastry, P. V. Parabrahma (1996), Rural Studies in Early Andhra, V.R. Publication, p. 59 Quote: "The modern Kamma sect of people in Andhra desa is originally of the Kapu families hailing from Kamma nadu or Kamma rashtra of the medieval period."
^Chari, Sharad (2004). Fraternal Capital. Stanford University Press. p. 162. ISBN0-8047-4873-X.
Fox, Richard G. (January 1969), "Varna Schemes and Ideological Integration in Indian Society", Comparative Studies in Society and History, 11 (01): 27-45, doi:10.1017/S0010417500005132: "When recognition of a regional varna scheme has been unavoidable--such as the tripartite division into Brahmins, non-Brahmins, and Untouchables in much of the South-- it has been explained in terms of an historical corruption or breakdown of the standard four-class system, rather than regarded as a functional entity in its own right."
Keiko, Yamada (2008), "Politics and representation of caste identity in regional historiography: A case study of Kammas in Andhra", The Indian Economic and Social History Review, 45 (3): 353-380, doi:10.1177/001946460804500302, (Subscription required (help))
Harrison, Selig S. (June 1956). "Caste and the Andhra Communists". The American Political Science Review. 50 (2): 378-404. JSTOR1951675. (Subscription required (help)).(subscription required)