Adaminaby was first settled as the township of Seymour in the 1860's. Initially the population of the area was sparse. John Cosgrove and Charles and Henry York were the first settlers and they named one of their large land holdings Adaminaby (properly spelt Adamindumee and possibly meaning 'resting place' or 'place of springs' in the local Aboriginal language). It was later to change its name to Adaminaby to avoid confusion with Seymour in Victoria.
For thirty years the country around Adaminaby remained sparsely settled by Europeans. The land was grazed but the living was hard. It wasn't until the discovery of gold at nearby Kiandra in 1859 that people began to move into the area in significant numbers. Being located midway between Cooma and Kiandra, the town became a convenient stopover point for gold prospectors.
Adaminaby was later to achieve fame as being the place where the Snowy Mountains Hydro Electric Scheme was officially launched on 17 October 1949. As Lake Eucumbene was to flood the area occupied by the town, the Government decided to move Adaminaby, starting in 1956, taking whole buildings across the Great Dividing Range to the new site, giving residents town water and electricity which was previously unavailable. The drowning of Adaminaby forms a unique chapter of Australia's history and as with the Snowy Scheme itself, it was a product of its time, and would be difficult if not impossible to achieve today.