A Subah was the term for a province (state) in the Mughal Empire. The term was also used by other polities of the Indian subcontinent. The word is derived from Arabic and Persian. The governor/ruler of a Subah was known as a subahdar (sometimes also referred to as a "Subeh"^[1]), which later became subedar to refer to an officer in the Indian Army and Pakistan Army. The subahs were established by badshah (emperor) Akbar during his administrative reforms of the years 1572–1580; initially, they numbered 12, but his conquests expanded the number of subahs to 15 by the end of his reign. Subahs were divided into Sarkars, or districts. Sarkars were further divided into Parganas or Mahals. His successors, most notably Aurangzeb, expanded the number of subahs further through their conquests. As the empire began to dissolve in the early 18th century, many subahs became effectively independent or were conquered by the Marathas or the British.

In the modern context, subah (Urdu: صوبہ) is a word used for province in the Urdu language mainly in Pakistan.

Initially, after the administrative reforms of Akbar, the Mughal empire was divided into 12 subahs: Kabul, Lahore, Multan, Delhi, Agra, Avadh, Illahabad, Bihar, Bangal, Malwa, Ajmer and Gujarat. After the conquest of Deccan, he created three more subahs there: Berar, Khandesh (initially renamed Dandesh in 1601) and Ahmadnagar (in 1636 renamed as Daulatabad and subsequently as Aurangabad).

Jahangir increased the number of subahs to 17 during his reign; Orissa being carved out of Bangal in 1607. The number of subahs increased to 22 under Shah Jahan.^[2] In his 8th regnal year, Shah Jahan separated the sarkar of Telangana from Berar and made it into a separate subah. In 1657, it was merged with Zafarabad Bidar subah. Agra was renamed Akbarabad in 1629 and Delhi became Shahjahanbad in 1648.^[3] Kashmir was carved out of Kabul, Thatta (Sindh) out of Multan, and Bidar out of Ahmadnagar. For some time Qandahar was a separate subah under the Mughal Empire but it was lost to Persia in 1648.

Aurangzeb added Bijapur (1686), Sira (1687)^[4] and Golkonda (1687) as new subahs. There were 22 subahs during his reign.^[2] These were Kabul, Kashmir, Lahore, Multan, Delhi, Agra, Avadh, Illahabad, Bihar, Bangalah, Orissa, Malwa, Ajmer, Gujarat, Berar, Khandesh, Aurangabad, Bidar, Thatta, Bijapur, Sira^[4] and Haidarabad (Golkonda).^[5] Aurangzeb made Arcot a Mughal subah in 1692.

The Sikh Empire (1799–1849), originating in the Punjab region, also used the term Suba for the provinces it administered under its territorial delineation, of which there were five.^[6]

In modern usage in Urdu language, the term is used as a word for province, while the word riyasat (Urdu: ریاست) ("princely state" in English) is used for (federated) state. The terminologies are based on the administrative structure of British India which was partially derived from the Mughal administrative structure. In modern times, the term subah is mainly used in Pakistan, where its four provinces are called "Subah" in the Urdu language.

• Administrative divisions of India