The land along the valley of the Highland Creek in Scarborough, Ontario was purchased in 1911 by Toronto-based businessman Miller Lash, who developed the site into his summer estate with a mansion, today known as the Miller Lash House. The mansion included 17 rooms, a barn, a coach house, and three houses for his staff to dwell. Over the following years, over 100 acres of the estate was also used as farmland. Following the death of Miller Lash in 1941, the estate was acquired by E. L. McLean, an insurance broker, in 1944 for $59,000. He made new additions to the estate, including a swimming pool and change room, and a retaining wall made in stone.