The building and design of Camden Park House, which preoccupied the mind of John Macarthur in the last years of his life, was begun by his sons, James and William, in 1832 and completed in 1835, a year after John's death.

Architect, John Verge, designed a mansion in the Palladian style with a central two-storey block with one-storey wings and extensions at each side. The rich farming heritage of the Macarthur region can be traced back to as early as 1795 when Governor Hunter went in search of stray cattle and found them settled by the Nepean River, in an area he later named "The Cowpastures", a name which is still in use today.

When John Macarthur was granted 5000 acres of the best pasture land in the colony, he promptly selected The Cowpastures and proceeded to establish Camden Park Estate, which became one of the finest estates in the nation.