Poole Harbour is essentially a drowned river valley. It was formed, along with Poole Bay, when a rising sea broke through the chalk ridge which had then connected Old Harry Rocks in Studland Bay with the Needles in the Isle of Wight. Geologists believe that this large river flowed eastwards from the Dartmoor region in Devon, carrying with it the massive deposits of flint, gravel and clay which are to be seen all the way to Hampshire. The Harbour as we know it was formed at the end of the last Ice Age around 7,000 years ago. Since then mudflats and salt marshes have developed, adding to the uniqueness of this beautiful Harbour.

There is strong archaeological evidence that sea levels in Poole Harbour were considerably lower in ancient times than they are today. It is therefore likely that prehistoric settlements around the Harbour are now beneath the waves. One artefact found off Brownsea Island is the Poole Logboat. This is 10 metres long and was cut from a giant oak tree. Dating to around 295BC it is our oldest evidence of the use of the Harbour.

Poole Quay circa. 1833

The Romans used Poole as an invasion port for their conquest of southern Britain. At the time of the Norman conquest Poole may have been a tiny fishing village. Huge deposits of oyster shells dating to late Saxon or early Norman times lie under Poole and Hamworthy Quays. The port steadily grew in importance and in 1433 was made Dorset's Port of the Staple. The 14th century Town Cellars were once used to store wool prior to export. Medieval Poole had trading links from the Baltic to Spain and Italy. The 17th century saw the start of a transatlantic trade which became vital to the town. In particular, trade with Newfoundland was the foundation of many fortunes among Poole merchants. In the early 18th century Poole had more ships trading with North America than any other English port.
 

The brig 'David' in 1864
One of the last of Poole's Newfoundland fleet of ships.