The steady growth of Camden Park's dairy herd through the 1800s was echoed by a similar growth of its sales of butter, cheese and milk to the Sydney market.
Camden Estate made butter for sale from the 1830s. In the early 1840s, on the initiative of Emily Macarthur, this became a full-scale enterprise when a commercial dairy complex was constructed near Belgenny lagoon in the vicinity of Camden Park House. The complex included a dairy building where cream was separated and churned into butter. There were adjacent cow yards, milking shed, milk-cooling shed and a pig yard. This was no backyard operation – the dairy complex represented a substantial investment for the estate, at a cost of £400.