The 1900 Belfast And Province Of Ulster Directory lists George Duffield, farmer living in Forthbrook Cottage in 1900. The Ordinance Map (survey in 1901) shows the cottage is close to where Duffield Park is today. An advert in the Belfast Telegraph in March 1941 states: "GRAZING. BALLYGONARTIN RD., BELFAST. I have been instructed by Mrs. DUFFIELD to LET for the Season, on the PREMISES, FORTHBROOK COTTAGE, BALLYGOMARTIN TRAM TERMINUS, BELFAST, on THURSDAY. 6th March, 1941, at 2-30 o'clock, APPROXIMATELY 30 ACRES OF GOOD GRAZING. Well watered and fenced. In Three Lots. Usual Credit". Clearly the land was sold at some point it was used for the building of Duffield Park. “On the recommendation of the city surveyor, the committee approved of the names: Ballygomartin Park and Duffield park for new streets off Ballygomartin Road and West Circular Rd respectively for Mr Joseph McMaster”. (14th February 1956).This street name is named for the townland: Ballygomartin Baile Gharraí Mháirtín "townland of Martin’s garden or enclosed field". “On the recommendation of the city surveyor, the committee approved of the names: Ballygomartin Park and Duffield park for new streets off Ballygomartin Road and West Circular Rd respectively for Mr Joseph McMaster”. (14th February 1956).