Douglas is the capital and largest town of the Isle of Man, with a population of 27,938 (2011). It is located at the mouth of the River Douglas, and on a sweeping bay of two miles (three kilometres). The River Douglas forms part of the town's harbour and main commercial port.

Douglas was a small settlement until it grew rapidly as a result of links with the English port of Liverpool in the 18th century. Further population growth came in the following century, resulting during the 1860s in a staged transfer of the High Courts, the Lieutenant Governor's residence, and finally the seat of the legislature, Tynwald, to Douglas from the ancient capital, Castletown.

The town is the Island's main hub for business, finance, legal services, shipping, transport, shopping, and entertainment. The annual Isle of Man TT motorcycle races start and finish in Douglas.

Douglas has a number of attractions and items of interest:

• The Tower of Refuge is a small castle-like shelter built upon Conister Rock in Douglas Bay as a sanctuary for shipwrecked sailors. Construction was instigated by Sir William Hillary, founder of the RNLI.
• Douglas Head is home to the Grand Union Camera Obscura which has recently undergone restoration and is open to the public during the summer months. Other artefacts and remnants of Victorian Tourism can still be found on walks around the area.
• The horse-drawn trams that run along the promenade from the Sea Terminal to the Manx Electric Railway station from spring to early autumn.
• Steam trains run 15 miles from Douglas railway station to Port Erin in the south of the Island.
• The Grandstand on Glencrutchery Road marks the start and finish of the annual TT Races and various other motorsports.
• The Gaiety Theatre and the Villa Marina are popular venues for all manner of stage acts: from rock music to comedy to drama to ballet. The Gaiety Theatre is one of the best surviving examples of the work of Frank Matcham and dates from 1900. Both venues have recently undergone extensive renovations.
• The award-winning Manx Museum in Kingswood Grove contains many of the most important cultural artefacts relating to the Manx nation. Highlights include the Calf of Man Crucifixion Stone, the Pagan Lady's necklace from the Viking excavations at Peel Castle, and the largest collection of Archibald Knox materials. It also houses the National Art Collection, and the National Archives.
• The Jubilee clock is a street clock built in 1887 to mark the Golden Jubilee of Queen Victoria's reign. It is located at the foot of Victoria Street and Loch Promenade. The location also marked the lower terminus of the Upper Douglas Cable Tramway
• Other buildings of interest include Isola restaurant, in John Street, and the Douglas Hotel, on the North Quay, both merchants' houses from the mid-18th century; the Castle Mona (formerly the Quality Hotel), a seaside mansion built by John Murray, 4th Duke of Atholl in 1804, awaiting refurbishment; and the Loch Promenade, a curving terrace of former boarding houses dating from the 1870s.

Douglas saw the first architectural essays of the Arts and Crafts architect Baillie Scott.

• The breakwater extension was built outside the existing smaller one, which carried a rail-mounted crane. It was completed in 1983 and opened by Princess Alexandra.
• The Sunken Gardens on Loch Promenade were created as a result of the widening of the promenade at the turn of the 20th century. A construction line was installed for this task.