By the early 1930s housing development was scattered across several locations: most was along Pelham Road, of which the majority was east of the original village (St Andrew's church), centred around the County Hotel, and close to the dock estate; further development had taken place south and south-east of the church, also on Pelham Road, in two locations each centred on one of the two nonconformist chapels. Almost all the housing was terraced, with the more generous ground plans found moving south-west along Pelham Road. By the mid-1930s the village had grown as much to require a comprehensive school which opened in 1936.
During the Second World War, John Dowland and Leonard Harrison received the George Cross for defusing a bomb that had fallen onto the grain ship SS Kildare in February 1940 in Immingham Dock. Development of new industries on the South Humber bank after the Second World War caused further growth of the town. By 1981 the population had risen to 11,506; making it North Lincolnshire's fourth town, after Grimsby, Cleethorpes and Scunthorpe.
The expansion of the village included: Eastfield County Junior School built in 1970; expansion of the comprehensive school, 1973; a shopping centre "Kennedy Way" constructed in 1965–7; and north of the centre 18 blocks of five storey flats constructed by George Wimpey from 1965; a Civic Centre also opened in 1965.
Standard housing also expanded: By 1968 there were many new side streets, in particular a new estate encompassed by Pilgrim Avenue; development along Pelham Road had become almost continuous, and the new village now expanding north-west towards the old Immingham. Further growth took place in the late 1960 and 1970s: north-west of Pelham Road, with the village continuous towards Church Lane; a new estate south-east of Pilgrim Road; as well as further infilling to the south-west.
Immingham Dock Station, originally part of the Barton and Immingham Light Railway closed in 1969,