Devizes serves as a centre for banks, solicitors and shops, with a large open market place where a market is held once a week. It has nearly five hundred listed buildings, a large open Green at the heart of the town, some notable churches and a Town Hall. Its development has grown around the 11th century Norman castle.
Devizes Castle was built by Osmund, Bishop of Salisbury in 1080, but the town is not mentioned in the Domesday Book. Because the castle was on the boundaries of the manors of Rowde, Bishops Cannings and Potterne it became known as the castrum ad divisas ("the castle at the boundaries"), hence the name Devizes. On John Speed's map of Wiltshire (1611), the town's name is recorded as The Devyses. The first castle on the site was of the motte and bailey form and was probably made of wood and earth, but this burnt down in 1113. A new castle was built in stone by Roger of Salisbury, Osmund's successor. Devizes received its first charter in 1141 permitting regular markets. The castle changed hands several times during the civil war between Stephen of Blois and Matilda in the 12th century. The castle held important prisoners, including Robert Curthose, eldest son of William the Conqueror in 1106. Robert was kept in Devizes for twenty years, before being moved to Cardiff Castle.
The town has had churches since the early 11th century. The town has four Church of England parish churches. The oldest is dedicated to St John the Baptist and was founded in 1130. Pevsner describes it as the second best Norman church in Wiltshire, after Malmesbury Abbey. It was the church intimately associated with the early Castle and its garrison. It is now a middle-of-the-road Church of England Church with a notable interior. The three others are dedicated to St Mary the Virgin, associated in its early days with the growing town of Devizes and now in a partnership with St John's, St James, part of Bishops Cannings until the end of the 19th century and now a low church, evangelical Anglican church, and St Peter's, originally a broad church for the canal side of the town but now a conservative, traditionalist, Anglo-Catholic church. A Roman Catholic church dedicated to Our Lady the Immaculate Conception was built in 1865 and has a Church primary school associated with and adjacent to it.
Devizes has a record of early dissenting preachers and churches. One church St. Mary's Chapel or the Congregational Church was founded on Northgate Street in 1776. It had two early charismatic preachers, the Reverend Robert Sloper and then the Reverend Richard Elliot, the anti-slavery campaigner. They regularly had congregations of over 500 in the early 19th century. This church has now been converted into one house and six apartments, and the congregation has united with the Methodist church to form St Andrew's United Church, on Long Street. There are two Baptist churches in the town, a Friends meeting house, and an Assemblies of God church.
During the 12th and 13th centuries the town of Devizes developed outside the castle with craftsmen and traders setting up businesses to serve the residents of the castle. The first known market in Devizes was in 1228. The original market was in the large space outside St Mary’s Church, rather than in the current Market Place, which at that time would have been within the castle’s outer bailey. The chief products in the 16th and early 17th centuries were wheat, wool and yarn, with cheese, bacon and butter increasing in importance later.
From the 16th century Devizes became known for its textiles, initially white woollen broadcloth but later the manufacture of serge, drugget, felt and cassimere or Zephyr cloth. In the early 18th century Devizes held the largest corn market in the West Country of England and also traded hops, cattle, horses and various cloth. Before the Corn Exchange was built in 1857 the trade in wheat and barley was conducted in the open, with sacks piled around the market cross. Today's cross displays the salutary tale of Ruth Pierce, accused of cheating some buyers at the market: The coroner, John Clare, recorded that she had been "struck down dead by the vengeance of God."
Wool merchants were able to build prosperous town houses in St. John's and Long Street and around the market place. From the end of the 18th century the manufacture of textiles declined, but other trades in the town included clock making, a bell foundry, booksellers, milliners, grocers and silversmiths. In the 18th century brewing, curing of tobacco and snuff-making were established in the town. Brewing still survives in the Wadworth Brewery, but the tobacco and snuff trades have now died out.
A new Devizes Prison, or "County House of Corrections", was opened in 1817. This replaced the Old Bridewell that had been built in Bridewell Street in 1579. The new prison was built of brick and stone, it was designed by Richard Ingleman as a two-storey polygon surrounding a central governor's house and reflected the panopticon principle. It had an operational life of more than ninety years and was closed in 1922. It stood on the north side of the Castle's Old Park, across the Kennet and Avon canal by way of a bridge still called the Prison Bridge. The House of Corrections was demolished by 1928.
Devizes has more than 500 listed buildings – a very large number for such a small town. The Trust for Devizes has a Town Map which provides a guide to many of them. Brownston House is a grade I listed building on New Park Street. It has been a home to four MPs, two Army Generals from 1700 and a young ladies' boarding school from 1859 to 1901. It was conserved in 1976 by Wiltshire Council and is now a business head office. Heathcote House on the Green in Devizes is a grade II* listed building. Its history is associated with the church and education. No 8 Long Street was the house of the clothier Samuel Powell, as well as Admiral Joseph Needham Tayler, one of the inspirations for C.S. Forester's fictional hero Horatio Hornblower. Southbroom House close to the Green was built in 1501. It burnt down and was rebuilt by the Eyles family in 1772. Southbroom House is now at the heart of Devizes School, a large comprehensive School in Devizes.
The Kennet and Avon Canal was built under the direction of John Rennie between 1794 and 1810 to link Devizes with Bristol and London. Near Devizes the canal rises by means of 29 locks, 16 of them in a straight line at Caen Hill. In the early days the canal was lit by gas lights at night, enabling boats to negotiate the locks at any time of day. The canal fell into disuse after the coming of the railway in the 1850s, but has been restored for leisure uses. There is a canal museum at Devizes Wharf.
In 1853 the Wiltshire Archaeological and Natural History Society was founded in the town, and later opened a museum in Long Street. Now called the Wiltshire Museum, the collections are designated as being of national significance. The museum has extensive Bronze Age collections and includes finds from the Stonehenge and Avebury World Heritage Site, including West Kennet Long Barrow, Marden Henge and Bush Barrow.
In 1857 the Wilts, Somerset and Weymouth Railway opened Devizes railway station and the branch line from Holt Junction, on its line between and . In 1862 the Great Western Railway extended its to line to meet this line, providing a direct line between and the West Country through Devizes. However the building of a by-pass line through removed most traffic from the Devizes line and British Rail closed it in 1966. Today the nearest railway stations are at Chippenham and .
The town is experiencing rapid housing growth, especially on its eastern fringe towards Andover.