‘Black Fen’ means a ‘dark-coloured marshy district’. The area now known as Blackfen was covered in woodland, farmland and streams until the 1920s. A large house, Queenswood, stood at the junction of Day’s Lane and Burnt Oak Lane with an entrance lodge on Blackfen Road. Residents included Sir John Kirkland, army agent and Brig. Gen. Sir Charles Martel of the Royal Arsenal, Woolwich. Another large house, Woodlands, stood on Blackfen Road, as well as several cottages including Merino Place. Cottages housing workers from Westwood Farm (now The Green, Falconwood), to which a footpath led from Blackfen Road, still stand. The original Woodman Public House had been built in 1845.

In the 1920s the sale of the Danson Estate, the electrification of the railway and the building of the Rochester Way prompted several developers to rapidly create estates of affordable houses. Soon, rows of shops began to appear. Churches, schools, a library and a cinema followed.

The shops have long been a focus of Blackfen life. Residents of the newly built houses could make use of a wide range of stores and the estate developers had offices dotted along Blackfen Road (C. R. Leech made use of the old Queenswood Lodge for his office). Local shop-keepers are still an important feature, offering a wide range of services.