In the mediaeval period, it consisted of two separate towns, Weymouth and Melcombe Regis, on either side of the harbour formed by the mouth of the river. These two towns never co-operated, and were quite hostile to each other, until the 16th century, when Elizabeth I forced them into co-operation by issuing a charter for a new borough, to be named Weymouth and Melcombe Regis.
Today, there is a jumble of old streets around the old town of Melcombe Regis, which is now the shopping centre, and the Seafront is beside this.
The old town of Weymouth is quite distinct on the other side of the river, connected by a bridge.
The Black Death arrived in England on a boat which landed at Weymouth in 1348, proceeding to kill a third of the country`s population. More positively, the port sent twenty ships to help Edward III`s siege of Calais and six to help resist the Spanish Armada.
John Endicott sailed from here in 1628 to found the New England plantation of Salem, Massachusetts. The American assault force embarked from Weymouth in 1944 on what would become known as D - Day.
Weymouth began to become fashionable thanks first to the efforts of the Bath entrepreneur Ralph Allen, and then by George III, who spent most of his Summers in the town from 1789. When he stepped out of his bathing machine into the water, a band would play "God Save the King".
There are still cross channel services from the harbour, now using catamarans. Trains used to run to a station at the harbour along the streets, to the amazement of visitors, until 1994.
In old Weymouth are a number of old houses, including the Tudor House. Brewers Quay is a major tourist attraction, carved out of an old brewery building, and including craft shops, a restaurant and the Weymouth Museum.
On the headland is Nothe Fort, constructed in the 1860s.
In the shopping centre, buildings include the Guildhall, built in 1836 on the site of the Melcombe Regis Guildhall, and the classical St. Mary`s Church, dating from 1815. This contains a Last Supper painted by Sir James Thornhill, whose most famous works are the paintings in the dome of St. Pauls Cathedral.
The Seafront occupies a long sweep of sandy bay, with a vista of cliffs in the background. The 1809 statue of George III is painted with jolly colours, as is the Jubilee Clock Tower.
Radipole Lake is now a bird sanctuary, and there is also a Sea Life Centre.
Nearby is the extraordinary Isle of Portland, as well as the even more extraordinary Chesil Bank.
Sir James Thornhill, painter, was born at Weymouth.
Blue Badge Guide Colin Crosby is available to lead Guided Walks around Weymouth for groups.