The district magistrate, also known as the district collector or deputy commissioner, is a career civil servant who serves as the executive head of a district's administration in India. The specific name depends on the state or union territory. Each of these posts has distinct responsibilities, and an officer can assume all of these roles at once. The district magistrate is primarily responsible for maintaining law and order, while the district collector focuses on land revenue administration, and the deputy commissioner is in charge of overseeing developmental activities and coordinates government departments. Additionally, they also serve as election officers, registrar, marriage officer, licensing authority, and managing disaster responses, among other things. While the specific scope of duties may vary from state to state, they are generally similar. The district magistrate comes under the general supervision of divisional commissioner.

Warren Hastings introduced the office of the District Collector in the Judicial Plan of 1772. By the Judicial Plan of 1774, the office of the Collector cum District Magistrate was temporarily renamed Diwan or Amil. The term Collector was brought back under the Judicial Plan of 1787. The name, Collector, derived from the holder being the head of the revenue organization (tax collection) for the district. With the passage of the Government of India Act 1858, by the British Parliament.

Sir George Campbell, lieutenant-governor of Bengal from 1871 to 1874, intended "to render the heads of districts no longer the drudges of many departments and masters of none, but in fact the general controlling authority over all departments in each district."

The office of a collector during the British Raj held multiple responsibilities – as collector, he was the head of the revenue organization, charged with registration, alteration, and partition of holdings; the settlement of disputes; the management of indebted estates; loans to agriculturists, and famine relief. As district magistrate, he exercised general supervision over the inferior courts and in particular, directed the police work. The office was meant to achieve the "peculiar purpose" of collecting revenue and of keeping the peace. The superintendent of police (SP), inspector general of jails, the surgeon general, the divisional forest officer (DFO) and the Executive Engineer PWD (EE) had to inform the collector of every activity in their departments.

Until the later part of the nineteenth century, no native was eligible to become a district collector. But with the introduction of open competitive examinations for the Indian Civil Service, the office was opened to natives. Romesh Chandra Dutt, Sripad Babaji Thakur, Anandaram Baruah, Krishna Govinda Gupta and Brajendranath De were the first five Indian ICS officers to become Collectors.

The district continued to be the unit of administration after India gained independence in 1947. The role of the district collector remained largely unchanged, except for the separation of most judicial powers to judicial officers of the district. Later, with the promulgation of the National Extension Services and Community Development Programme by the Nehru government in 1952, the district collector was entrusted with the additional responsibility of implementing the Government of India's development programs in the district.

The nomenclature of the office of the district head is a legacy of the administrative practices of British India. Although the functions and powers of the officer were largely uniform across the country, the designation often reflected the primary responsibility associated with the office in a particular province. In the Bengal Presidency, the post was known as District Magistrate and Collector, whereas in the Bombay Presidency and the Central Provinces it was generally referred to as the District Collector, even though the officer also exercised magisterial powers. In the Madras Presidency, the office was more commonly styled simply as Collector.

In the United Provinces, where the maintenance of law and order was regarded as the foremost duty, the designation District Magistrate came into use and continues in present-day Uttar Pradesh. In several non-regulation provinces such as Punjab, Burma, Assam and Oudh, a simplified system of administration was followed, with many provisions of the Criminal Procedure Code kept in abeyance. In these regions, the District Magistrate also functioned as the District and Sessions Judge, and the office came to be designated as the Deputy Commissioner. This usage arose because such provinces were administered by a Chief Commissioner, who combined the roles of Governor and High Court by exercising both executive and judicial authority.