The dock was constructed at the site of Dagenham Breach, an area of flooded marsh caused by the breaching of the sea wall in 1707, and repeatedly flooded in the 18th Century. After a number of failed attempts, in 1865 Sir John Rennie built a jetty and a branch railway, but the company failed financially. The site was acquired and Dagenham Dock was constructed over from 1887 by Samuel Williams. Historic records of Samuel Williams & Sons and John Hudson Ltd are held at Barking and Dagenham Archive Service, Valence House Museum although the full collection has not yet been fully catalogued.