Longest ever reigns
Who
Phiops II, Minhti, King of Arakan,, Musoma Kanijo
Where
Arakan ()

Minhti, King of Arakan, which is now part of Myanmar (formerly Burma), is reputed to have reigned for 95 years between 1279 and 1374.

The longest documented reign of any monarch is that of Phiops II (also known as Pepi II or Neferkare) a Sixth-Dynasty pharaoh of ancient Egypt. His reign began c. 2281BC, when he was 6 years of age, and is believed to have lasted c. 94 years.

Musoma Kanijo, although not a monarch, was chief of the Nzega district of western Tanganyika (now part of Tanzania) and reputedly reigned for more than 98 years from 1864, when aged 8, until his death on 2 February 1963.