Adelaide Crescent is a mid-19th-century residential development in Hove, part of the English city and seaside resort of Brighton and Hove. Conceived as an ambitious attempt to rival the large, high-class Kemp Town estate east of Brighton, the crescent was not built to its original plan because time and money were insufficient. Nevertheless, together with its northerly neighbour Palmeira Square (with which it is continuous), it forms one of Hove's most important architectural set-pieces.

Building work started in 1830 to the design of Decimus Burton. The adjacent land was originally occupied by "the world's largest conservatory", the Anthaeum; its collapse stopped construction of the crescent, which did not resume until the 1850s. The original design was modified and the crescent was eventually finished in the mid-1860s. Together with the Kemp Town and Brunswick Town estates, the crescent is one of the foremost pre-Victorian residential developments in the Brighton area: it has been claimed that "outside Bath, [they] have no superior in England". The buildings in the main part of Adelaide Crescent are Grade II* listed. Some of the associated buildings at the sea-facing south end are listed at the lower Grade II.

Adelaide Crescent is immediately behind Hove seafront, bounded by Kingsway (the coast road) to the south and Palmeira Square to the north. The earlier Brunswick Town estate of Brunswick Square, Brunswick Terrace and its associated buildings are to the east. It developed at the west edge of the Wick Estate, whose western boundary is the present St John's Road. This 250-acre (100 ha) estate, based on a farm of the same name, covered open land east of Hove village as far as the parish boundary with Brighton. Although it was within Hove parish, the crescent and Brunswick Town were originally considered "scarcely part of Hove at all", because they were distant from the village but adjoined the western edge of Brighton. Furthermore, their architectural character aligned them more closely with Brighton, as did their historical associations.

The crescent forms part of the Brunswick and Adelaide ward of the city Brighton and Hove. This has the highest population density of any ward in Britain. As of 2013^[update] it is one of 21 wards in the city.

Brighton was a small town based on fishing and agriculture until the early 18th century, after which it experienced several phases of rapid growth and developed into a large, fashionable seaside resort. Its western neighbour, Hove, was still a small village well into the 19th century, though, its development being constrained because the land around it was divided into several estates owned by wealthy local families. One of these was the Wick Estate. Owned after the Norman conquest by the de Pierpoints, it was bought in 1573 by the Stapley family, of which Anthony Stapley became famous as one of the regicides of King Charles I. In 1701 it was acquired by the Scutt family from Brighton, and in the 1820s it passed to Thomas Read Kemp. He intended to replicate his Kemp Town development—an architectural set-piece of high-class houses set in crescents, squares and terraces around central gardens, built in the 1820s east of Brighton—but could not afford to do so, although the plans were announced in the Sussex Advertiser newspaper in 1825 and in other media. (14 March 1825 edition of the Sussex Advertiser claimed that "Kemp Town east and Kemp Town west would be a splendid addition to Brighton".) In 1830 he sold the land to Sir Isaac Goldsmid, 1st Baronet for £60,000 (£5,930,000 as of 2025).

Most of the Wick Estate's 250 acres (100 ha) of land lay north of the present Western Road. This main east–west road links Brighton and Hove and was developed from the early 19th century; originally it was a merely a narrow path between fields. Just under 50 acres (20 ha) lay between it and the sea; 25 acres (10 ha) was developed in the 1820s as the Brunswick Town estate, leaving the southwest corner of the estate undeveloped apart from a brickworks and a footpath leading to St Andrew's parish church. In 1830, Goldsmid commissioned architect Decimus Burton to design a crescent of high-class houses which would be built on the site. Burton exhibited his designs at the Royal Academy the following year. Building work started in December 1830, and Goldsmid sought William IV's permission to name the development after the queen consort Adelaide of Saxe-Meiningen. Accordingly, it was officially named Queen Adelaide Crescent. (The name Royal Adelaide Crescent was occasionally used as well, but it was soon shortened to its present form. The original name was still in use for legal purposes until 1873 or later, though.)

The original design, as exhibited at the Royal Academy, consisted of a half-moon-shaped sea-facing crescent similar to, but much larger than, the earlier Royal Crescent in Brighton. Between 1830 and 1834, ten houses were completed in accordance with this layout: numbers 1–3 (originally called Queen Adelaide Terrace) faced the sea and formed a terminating feature of the crescent, and numbers 4–10 curved inland to the northwest. At the time, Burton was also working with his father James on the new resort of St Leonards-on-Sea further along the coast; accordingly he did little more than "provide the general design of the façades", and the construction work was carried out by local architecture and building firm G. Cheesman and Sons.

At the same time, the Anthaeum was being built immediately to the north. This grandiose project was conceived by botanist, landscape gardener and writer Henry Phillips in conjunction with architect Amon Henry Wilds. Under the world's largest dome would be a 1.5-acre (0.61 ha) tropical garden filled with exotic shrubs, flowers, birds and fish. Construction work took place in 1832–33, but the builders removed a supporting pillar crucial to the design and took away temporary scaffolding holding up the glazed dome. On its opening day in 1833, the structure spectacularly collapsed, shocking Phillips so much he went blind. The wreckage lay where it fell for the next 20 years. After the disaster there was a long delay in building work on Adelaide Crescent, and Burton's semicircular design was abandoned; Goldsmid, who gave land and money towards the Anthaeum scheme, may have lost enthusiasm for the project, although there is no firm evidence for the cause of the delay.