Yan Yean Reservoir is the oldest water supply for the city of Melbourne, Victoria, Australia.

[3] Construction took place at the height of the gold rush[5] employing a tent city of 1,000 workers returning from the goldfields.

[10] It was designed by James Blackburn, an English civil engineer and former London sanitary inspector who was transported to Tasmania as a convict following charges of embezzlement.

[2][3] Photographer Fred Kruger was commissioned by the government to provide images of the extensive works for display at the Colonial and Indian Exhibition of 1886.

[13] The reservoir resisted a flood that hit Melbourne in 1923, and became the city's main water emergency resource after the incident.

[10] The site of the reservoir is 183 metres in altitude, allowing sufficient hydraulic head for the water to be piped throughout the city under gravity.

Species include musk duck, Australasian grebe, great crested grebe, white-faced heron, dusky moorhen, Eurasian coot, Latham's snipe, musk lorikeet, eastern rosella, superb fairywren, red wattlebird, grey butcherbird and grey fantail.