The following structure of the Frontier Corps applied in 1921
These units were not “regiments” of the Indian Army, rather they were armed para-military units paid for by the civil purse and under the control of the local Political Agent. Officers were seconded from the Indian Army.
- Kurram Militia
- North Waziristan Militia later replaced by the Tochi Scouts
- South Waziristan Militia later replaced by South Waziristan Scouts
- Mohmand Militia . In 1922 merged into the Frontier Constabulary
- Chitral Scouts
- Zhob Militia
- Mekran Levy Corps
- Gilgit Scouts
The Khyber Rifles was a similar type of unit which had been disbanded in 1919.
- "Scouting On The Afghan Frontier" by Leonard Richards November 1, 2002 Legion Magazine, Canada. Memories of 1944-46 . The author was with the Tochi Scouts at Dosalli Post and later with the Zhob Militia in Baluchistan, at Left wing’s headquarters at Sambaza, and Fort Sandeman, the headquarters.
- "Guardians of the Frontier" KPK Tribune, now an archived webpage.
- Watercolour: Subadar of the Kurram Militia c 1908 National Army Museum
- Photograph: Kurram Militia Post by Randolph Bezzant Holmes c 1919. library.duke.edu
- Irksome and Unpopular Duties: Pakistan's Frontier Corps, Local Security Forces and Counterinsurgency by William G Rosenau 2012. Paper for Center for Naval Analyses, VA USA. Archive.org. Includes a chapter on Origins.
- Map: "North-West Frontier Province and Kashmir and Jammu" p. 35. Imperial Gazetteer of India, v. 26, Atlas 1931 edition. dsal.uchicago.edu
Historical books online
- The Frontier Scouts by Charles Chenevix Trench 1985. Link to a pdf download, PAHAR - Mountains of Central Asia Digital Dataset (MCADD). If the download button does not display, locate under Books/Indian Subcontinent/1985. Also available Archive.org Books to Borrow/Lending Library.
- The Great Wall of India by Ian Hay [John Hay Beith] 1933. Archive.org. The author visited a friend at Chashmai Fort. This is probably a fictional name. The friend worked for an unnamed Frontier Corps or similar. "Best guess" is Tochi Scouts, based at Miranshah.
- Officers employed with Frontier Corps April 1933 Indian Army List, page 889 Archive.org
- Page 313 A Concise History of Afghanistan in 25 Volumes, Volume 1 by Hamid Wahed Alikuzai Google Books
- The Transfrontier Corps page 144 Edge of Empire: The British Political Officer and Tribal Administration on the North-West Frontier, 1877-1947 by Christian Tripodi Google Books
- References to the Kurram Militia: page 58 Nothing But!: Book Two: The Long Road To Freedom by Brigadier Samir Bhattacharya Google Books
- An Illustrated History of Chitral Scouts 1903-2014 by Major Aamir Mushtaq Cheema 2014 Archive.org
- "Ants" by W J Blackledge, page 471 Fifty Amazing Hairbreadth Escapes c 1937. Archive.org. Stated to be an extract from Hell’s Broth Militia 
- "Company of the Damned" by Captain W J Blackledge. An Inside Picture of the Hunted Men’s Militia [Kurram Militia] in India. The story of Digger Craven, second in command. Appeared in issues of the weekly magazine Liberty from v13n14 1936-4-4. Part 1, part 2, part 3 Further episodes are not available online.
- An examination of Part 1 shows it is an abridged version of "Ants" which in turn is an extract from Hell’s Broth Militia. Note some classify the latter as biography.