Colonel Colin Mackenzie CB (1754–8 May 1821) was a Scottish army officer in the British East India Company who later became the first Surveyor General of India. He was a collector of antiquities and an orientalist and an indologist. He surveyed southern India, making use of local interpreters and scholars to study religion, oral histories, inscriptions and other evidence, initially out of personal interest, and later as a surveyor. He was ordered to survey the Mysore region shortly after the British victory over Tipu Sultan in 1799 and produced the first maps of the region along with illustrations of the landscape and notes on archaeological landmarks. His collections consisting of thousands of manuscripts, inscriptions, translations, coins and paintings, which were acquired after his death by the India Office Library and are an important source for the study of Indian history. He was appointed Companion of the Order of the Bath on 4 June 1815.

Colonel Colin Mackenzie was born in Stornoway on Lewis, Outer Hebrides, Scotland, the second son of merchant Murdoch Mackenzie (who was the first postmaster of the town) and Barbara around 1753 or 1754. Little is known of his early life but he is thought to have started his work as a Comptroller of the Customs at Stornoway from 1778 to 1783, possibly through the influence of his father's association with the Mackenzie Earls of Seaforth. In his youth he had an interest in mathematics possibly fostered by his schoolmaster, a freemason, Alexander Anderson. Lord Kenneth Mackenzie (last Earl of Seaforth) and Francis (fifth Lord Napier) sought his help in preparing a biography of John Napier and his work on logarithms. When Lord Napier died in 1773, Kenneth Mackenzie helped Colin to obtain commission with the British East India Company to join the Madras Army. When he arrived in Madras on 2 September 1783 he was thirty and was never to return home again. He went to India as a volunteer in the 78th Seaforth Highlanders, joined in India as a Cadet in the Infantry division but transferred in 1786 as a Cadet of Engineers.

Arriving in India he first met the daughter of Lord Francis Napier, Hester (d. 1819). Hester was married to Samuel Johnston who worked as a civil servant at Madurai (their son Alexander Johnston later became a judge in Sri Lanka, founded the Royal Asiatic Society of Great Britain and Ireland and wrote a memoir on the life of Colin Mackenzie). Hester introduced Mackenzie to some Brahmins to obtain information on Hindu mathematical traditions as part of the biographical memoir on John Napier and the history of logarithms. The biography project appears to have been subsequently dropped but Colin continued to take an interest in antiquities.

For the first thirteen years in India, he was busy with military duties. He began in Coimbatore and Dindigul around 1783 followed by engineering duties in Madras, Nellore and Guntur and during the campaign against Mysore from 1790 to 1792. In 1793 he saw action in the Siege of Pondicherry. He was posted as a commanding engineer to Ceylon and returned in 1796. He rose in rank starting from a second lieutenant on 16 May 1783, first lieutenant on 6 March 1789; and captain 16 August 1793. Major by 1 Jan 1806 rising on to become a colonel on 12 August 1819. It was after his return from Ceylon that he was able to follow his interest in antiquities.

In 1799, Mackenzie was part of the British force in the Battle of Seringapatam, where Tipu Sultan, Sultan of Mysore was defeated. After the defeat of Tipu, he led the Mysore survey between 1799 and 1810 and one of the aims was to establish the boundaries of the state as well as the territories ceded by the Nizam. The survey consisted of interpreters, a team of draftsmen and illustrators who collected material on the natural history, geography, architecture, history, customs, and folk tales of the region. There were also some surveyors who had been trained by Michael Topping at the surveying school in Madras. Some of these surveyors came from the Madras Orphan Asylum including William Lantwar, John Gould, John Mustie and John Newman. Another of Mackenzie's assistant was Benjamin Swain Ward who had trained in England.

When he began the survey, he was concerned that he had no linguistic skills and was more appalled by the lack of British competence in south Indian languages. Around the same time, the trigonometric survey was proposed by William Lambton but there was little collaboration between the two during the Mysore survey. Mackenzie was told that his survey was not to be "mere military or geographical information, but that your enquiries are to be extended to a statistical account of the whole country." However he was not provided enough resources for this grand plan. He wrote to Barry Close that he would not "descend to the minutiae" of measuring cultivated and uncultivated land but would instead focus on that which was of political and military importance. He pointed out that enquiries into revenues created uneasiness. One of his chief interpreters was a Niyogi Brahmin named Kavelli Venkata Boria (IAST kāvelī veṃkeṭā boraiyāḥ, there are variations in spelling) who Mackenzie first met in 1796, shortly after his return from Ceylon. He found Boria capable of dealing with all sects and considered him as "the first step of my introduction into the portal of Indian knowledge." Boria knew Tamil, Telugu, Kannada and Sankskrit. In 1797, Mackenzie visited Mudgeri and found the ruins of a Jain temple. He wrote an extensive note on the Jains based on interviews through his translator "Cavelly Boria". Boria died in 1803 and Mackenzie took in his brother Venkata Lechmiah (IAST lakṣmaiyyā, also spelt Lakshmaiah or Lakshmayya). Another of Mackenzie's assistant was Dhurmiah (IAST dharmayāḥ), a Jain pandit (scholar) from Maleyur, then in Mysore State. Dhurmiah, with his ability to read Hale Kannada (old Kannada) inscriptions contributed greatly to the study of the inscriptions in the region. Dhurmiah provided Mackenzie with Jain insights into the history of India but some ideas were considered too unreliable such as the idea that the Jains had fled from Mecca. Dhurmiah's son may also have been on Mackenzie's staff. Another orientalist, Mark Wilks interviewed Dhurmiah and wrote on the Jains in his 1817 Historical Sketches of the South of India.

Stating the aims of his survey, he wrote from the perspective of a historian in a letter to Major Merwick Shawe in 1805:

The elucidation of the History of the several Governments that have rapidly succeeded in this Stage will I conceived be very interesting, as by the Inscriptions, Grants & other Documents that came into my hands, a regular Progress is traced up to the first Mahomedan invasion in the 13th Century & even beyond it to the 8th but more obscurely; & in several instances still further, these consist not merely of a dry Chain of uninteresting facts but are connected by various illustrations of the genious & manner of the People, their Several Systems of Government & of Religion, & of the predominant causes that influence their Sentiments & opinions to this day; lights are derived on the Tenures of lands, the origin & variety of the several classes, and the genius and Spirit of the Government prevalent generally in the South for centuries from Several Documents illustrating claims & pretension not foreign to modern discussions; ... confirming the utility of this undertaking to the existing Government from a knowledge of Institutions that influence so considerable a part of the Population of the Empire.