Port Glasgow expanded up the steep hills inland to open fields where areas such as Park Farm, Boglestone, Slaemuir and Devol and Oronsay were founded.

The origins of Port Glasgow go back to the construction by Sir George Maxwell between 1450 and 1477 of the "New Werke of Finlastoun", which became Newark Castle.

After 1589 the village of Greenock formed just under 4 miles (6 kilometres) to the west of Newark, and gradually became a market town with growing fishing and sea trade, although it had only a jetty in the bay to unload ships.

Construction of piers and breakwaters enclosing the harbour began promptly, and Newport Glasgow was constituted as a free port.

[5][6] Trade prospered quickly, and by 1710 Newport Glasgow had the principal Clyde custom house, initially in Customhouse Lane, then after 1754 in a new building constructed on the west quay of the harbour.

Ships, mostly owned by Glasgow merchants, imported tobacco, sugar, rum, cotton and mahogany from the Americas, as well as timber, iron and hemp from the Baltic.

A change began in 1773 when the Lang Dyke was constructed to deepen the upper river, and ships increasingly went upriver straight to Glasgow.

[14] The former Gourock Ropeworks building, built as a sugar refinery in 1866, was redeveloped as luxury flats in 2006,[15] and a retail park has been laid out adjacent to the town centre.

Both stations are on the electrified Inverclyde Line, which has frequent services to the termini at Glasgow Central, Gourock and Wemyss Bay.

A park and waterfront walkway have been constructed to the east, on the site of Lamont's shipyard and Smith & Houston's shipbreaking yard.

[21] About 1 mile (1.5 kilometres) upstream from the castle and its surrounding park, several acres of the Clyde foreshore at Parklea are owned by the National Trust for Scotland.

It contains a memorial to the Clyde boating tragedy when 20 people died when a pleasure cruiser capsized in bad weather on 14 September 1947.