Until about 1760 Dunball was a low lying promontory used for grazing animals in the parish of Easton in Gordano. It was the most northerly part of Somerset. Its position forced the River Avon to make a sharp turn to the north in order to reach the Severn Estuary. By around 1770 the river had begun to cut a channel across the promontory, which meant that at high tide small boats could take a straight course from the Severn Estuary to Pill. Over the next 90 years the channel, which became known as the Swash, deepened and Dunball became an island of around 20-25 acres in size. The original North Channel of the River Avon began to silt up at the same time.
A gibbet was erected on Dunball in the 18th century. Gibbets were structures on which the dead bodies of executed criminals were displayed as deterrents to existing or potential criminals. The remains of Dunball’s gibbet were still in existence when the Ordnance Survey surveyed the area between 1880 and 1882.
A 1:10,560 scale first edition Ordnance Survey map dated 1884-1887 and showing Dunball and also the Swash and North Channels, can be seen here: http://www1.somerset.gov.uk/archives/Maps/OS61htm/0203.htm
In 1857 Dunball Island was bought by Mr John Cook Hooper, the landlord of the Marine Hotel in Avonmouth for £100. He sold it to Bristol Corporation in 1860 for £856. Between the late 1860s and the mid-1870s the North Channel silted up and then disappeared and Dunball became attached to Gloucestershire sometime after 1875. In 1894 Dunball and Avonmouth were incorporated into the City of Bristol.
Dunball’s short life came to an end when it was destroyed during the construction of the Royal Edward Dock and adjacent Graving Dock at Avonmouth between 1902 and 1908. Dunball was still marked on the 1904 Ordnance Survey map but by this time it was no longer an island. It had disappeared altogether by the time of the 1912 revision map.
A 1:10,560 scale second edition Ordnance Survey map dated c1900 and showing Dunball can be seen here: http://www1.somerset.gov.uk/archives/Maps/OS62htm/0203.htm