Adamson Estate, Heritage manor house near Lake Ontario in Mississauga, Canada.

The Adamson Estate is a Flemish-style mansion that Agar Adamson designed and built in 1919 after returning from service in France during the First World War. The main house, often mistaken for Spanish, stands on land that was part of Grove Farm, a wedding gift to Agar Adamson and Mabel Cawthra. In 1943 his son Anthony Adamson added a separate house on the property. The estate forms the eastern boundary of Port Credit and is now a public park on the Waterfront Trail.

Joseph Cawthra acquired the land in 1809, and the farmland later known as Grove Farm was given to Agar Adamson and Mabel Cawthra as a wedding gift. Agar Adamson, born on Christmas Day 1865, designed and built the Flemish-style mansion in 1919 after serving in France during the First World War. His son Anthony added a house of his own on the property in 1943. The Credit Valley Conservation Authority bought the estate from the Adamson family in 1975, and it was recognized as a Historic Place in 1978.

The estate's name links to Agar Adamson, who married Mabel Cawthra and received the farmland as a wedding gift; the Cawthra family fortune came from supplying eastern white pine logs for British Royal Navy ship masts. The great eastern white pines still standing on the grounds tie the site to that family history and to the early development of Toronto Township, now Mississauga. A family pet cemetery, enclosed by a wrought iron fence with stone pillars and a memorial plaque, can be seen on the property.

The property is situated on Enola Avenue and functions as a public park open from sunrise until evening, with multiple pathways connecting through the gardens and to nearby waterfront trails. Self-guided exploration is easy, and visitors can choose walking routes of varying length.

The great eastern white pine trees still standing on the grounds link the estate to the Cawthra family fortune, built on supplying white pine logs for British Royal Navy ship masts. A pet cemetery on the property is now enclosed by a wrought iron fence with stone pillars and a memorial plaque.