This bulletin presents information on the youth detention population in Australia, focusing on quarterly trends from June 2011 to June 2015. There were fewer than 900 young people in detention on an average night in the June quarter 2015, just over half (55%) of whom were unsentenced. Numbers and rates of young people in detention dropped slightly over the 4 years, but trends varied among the states and territories. Just over half (54%) of all young people in detention on an average night were Indigenous.