Siryfion Sir Drefaldwyn yn yr 20fed ganrif

Mae hon yn rhestr (anghyflawn) o ddeiliaid swydd Siryf Sir Drefaldwyn rhwng 1900 a 1974

• 1900: Capt. Peter Audley David Arthur Llanerchydol^[1]
• 1901: Arthur Watkin Williams-Wynn, Coed-y-Maen, Meifod
• 1902: Hugh Lewis, Glanhafren, Penystrywaid
• 1903: John Naylor, Plas Tre'r-llai, Leighton
• 1904: Edward Arthur Field Whittel Herbert, Upper Helmsley Hall, Efrog.
• 1905: Daniel Wintringham Stable, Plas Llwyn Owen, Llanbrynmair
• 1906: Sydney Rankin Heap, Mellington, Yr Ystog
• 1907: Hugh Edmund Ethelston Peel, Neuadd Llandrinio
• 1908: Arthur Erskin Owen Humphreys-Owen, Glansevern, Aberriw
• 1909: Noel James Price Turner, Neuadd Sylfaen, Y Trallwng.

• 1910: Yr Arglwydd Herbert Lionel Vane Tempest-, Y Plas, Machynlleth
• 1911: Edward Jones, Maesmawr, Llandinam
• 1912: William Henry Burton Swift, Crescent House, Y Drenewydd.
• 1913: William John Corbett-Winder, Vaynor, Aberriw
• 1914: John Murray Naylor, Leighton
• 1915: Reuben Norton
• 1916: Major Hugh Edward Bonsall
• 1917: John Bancroft Williams, Dolforgan, Ceri
• 1918: Reginald Quayle Wilson, Brooklands, Y Trallwng
• 1919: Uwchfrigadydd Arthur Edmund Sandbach, Bryngwyn, Llanfechain

• 1920: Uwchgapten Harmood Harmood-Baner, Caerhowel, Trefaldwyn
• 1921: Samuel Arthur Sampson, Dysserth, Y Trallwng
• 1922: William Henry Perry Leslie, Bryntanat, Llansantffraid
• 1923: Pryce Pryce-Edward Jones
• 1924: Robert Carey Chapple Gill, Blwchycibau
• 1925: Herbert Arthur Openshaw, Brongain, Llanfechain
• 1926: Donald Walter Macpherson, Ceri
• 1927: William Marsahll Dugdale, Llanfyllin
• 1928: Henry Hall Platt, Llanymynech
• 1929: Arthur Lloyd Owen Owen, Machynlleth

• 1930: Francis Reynolds Verdon, Y Trallwng
• 1931: Hector Carlisle Pilkington, Bryn Tanat, Llansantffraid
• 1932: Yr Arglwydd Davies, Llandinam
• 1933: Humphrey Dod Lynes, Castell Caereinion
• 1934: Dr Alfred Shearer, Y Drenewydd
• 1935: Dr. William Henry Lewis, Llansantffraid
• 1936: Arthur Loftus Onslow, Llanidloes
• 1937: Major William John Burdon Evans, Y Drenewydd
• 1938: John Howell Evans, Llundain a Phont Dolanog
• 1939: Evan Emrys Jones, Caersŵs

• 1940: John Davies Knatchbull Lloyd, Trefaldwyn
• 1941: Syr Charles Gerald Trevor, Cegidfa.
• 1942: Harri Morgan, Burnham, Bucks a'r Drenewydd
• 1943: Christine Stella Way, Aberriw
• 1944: Col. Charles Stafford Price-Davies, Marrington, Llanffynhonwen
• 1945: Thomas Evan Kinsey, Caersŵs
• 1946: Marguerite Frances Hanmer, Llanbrynmair
• 1947: Jano Clement Davies, Meifod
• 1948: Edward William Minton-Beddoes, Church Stretton, Swydd Amwythig a Dolfor
• 1949: Syr George Frederick Hamer, Llanidloes.
• 1950: Uwchgapten Robert John Brymer-Griffith, Bryneira, Y Drenewydd, Sir Drefaldwyn.

• 1951: Yr Anrh. William Rupert Davies, Neuadd Brookland, Y Trallwng, Sir Drefaldwyn.
• 1952: Dr. Richard Davies-Jones, Llys Hafren, Llanidloes
• 1953: Robert William Griffiths, Woodlands, Ffordun, ger Y Trallwng
• 1954: Thomas Williams, Ffordun
• 1955: Major William Mason Marriott, CBE, Park House, Parc Castell Powys, Y Trallwng.
• 1956: Capten Edward Calcott Pryce, Cegidfa
• 1957:. Hywel Wynn Owen, The Moorings, Y Trallwng
• 1957: Ralph Edward Blackett Beaumont
• 1958: Y Ledi Sybil Dorothy Vaughan Hamer
• 1959: Uwchgapten John Eldon Marshall Dugdale, TO, The Forest, Ceri, Y Drenewydd

• 1960: Y Ledi Lucie Haden Stable, Llanbrynmair
• 1961: Yr Athro David Vaughan Davies, Llanidloes a Llundain
• 1962: Mawr Hugh Meredith Peter Lewis, TD, Neuadd Milford, Y Drenewydd.
• 1963: Charles Lionel Joce Humphreys, Aberriw
• 1964:. David Philip Davies, Stalloe, Trefaldwyn
• 1965:. John Edfryn Jones, Henblas, Caersŵs
• 1966: Joyce Daphne Howard, Buttington
• 1967: Dr. Nicholas Bennett-Jones, Plas-y-Coed, Y Drenewydd
• 1968:. Alun Meurig Jones, Court Calmore, Trefaldwyn.
• 1969: Yr Anrh. Edward David Grant Davies, Cefngwyfed, Tregynon.

• 1970: John Kynaston Williams, Cegidfa
• 1971: Cecil Edward Vaughan Owen, Llanidloes
• 1972: Stephen Williams, Neuadd Black, Y Drenewydd.