Upwards of 1,000 people were at Yan Yean during the construction works, which were completed in 1857. A primary school was opened in 1858, a short-lived post office began the following year and church services began. Yan Yean extended northwards to Barber's Creek and to South Yan Yean which in 1913 was re-named Mernda . The reservoir was a favourite destination for excursionists, stimulating the building of two hotels. As metropolitan Melbourne has edged towards Yan Yean poultry, horse and dog breeding have developed, but cattle grazing is dominant.
Many farmers depend on supplementary non-farm income.
The township remains small with a general store and primary school. A History , Yan Yean School Council, 1978. A Centenary History of the Whittlesea Shire , Lowden Publishing Co., 1975.