The inaugral Australian Junior Championship was held in 1949. The first Australian Girls Championship was held in 1960.
The list of past U18 Open and Girls Champions is on Wikipedia.
The Australian Junior Chess Championships have been held in Queensland 3 other times since the turn of the century. In 2006, the tournament was held at Carlton Crest Hotel in Brisbane City, in 2013 the tournament was held at Bond University on the Gold Coast, and in 2017 the tournament was held at Anglican Church Grammar in East Brisbane.