|Locations of interest|
|First appearance||Myst: The Book of Ti'ana|
Ko'ah was the personal retreat Age of Aitrus' family, written for them when his father, Kahlis, was promoted to Grand Master of the Guild of Surveyors. The Age is described as rolling pasture punctuated by small groves of trees, and bordered by a line of mountains. It was the birthplace of Gehn. It was rediscovered by Atrus when he was searching the D'ni ruins.