The town lies below the northwestern edge of Salisbury Plain, about 4 miles (6 km) south of Trowbridge and a similar distance north of Warminster.

Westbury was known for the annual Hill Fair where many sheep were sold in the 18th and 19th centuries; later growth came from the town's position at the intersection of two railway lines.

[6] Westbury centres on its historic marketplace – although markets ceased to be held in the middle of the 19th century[5] – and the All Saints' Church.

That company was bought by the Great Western Railway in 1850, who over the next few years built lines onwards to Frome (to access the Somerset coalfield), then south to Yeovil and Weymouth, as well as southeast from Westbury to Warminster and then Salisbury.

Its planned disposal was announced in March 2016,[12] and later that year the MoD estimated that the Selection Board would move to Sandhurst by 2024.

[13] A band of Late Jurassic Kimmeridge Clay runs under England from an outcrop on the Dorset coast and comes close to the surface around Westbury.

[14] Many marine fossils have been found in the pits dug for the cement works north-east of the town,[14] notably the almost complete skull and 2-metre (6 ft) lower jaw of a new species which was named Pliosaurus carpenteri after its 1994 discoverer, Simon Carpenter.

[18] Iron ore was discovered just north of the town in the 1840s during construction of the railway; opencast mines were developed and furnaces built.

[5] The most likely origin of the West- in Westbury is simply that the town is near the western edge of the county of Wiltshire, the bounds of which have been much the same since the Anglo-Saxon period.

The majority of local government functions (including schools, roads, social services, waste disposal, emergency planning, leisure services, development control, refuse collection and street cleaning) are carried out by Wiltshire Council, a unitary authority.

[21] Westbury is a civil parish with an elected town council of fifteen members: five for each of three wards with the same boundaries as the electoral divisions.

The council also runs the Grade II listed Laverton Institute which serves as the town hall and as a venue for events and meetings.

Nearby villages are Bratton, Chapmanslade, Dilton Marsh, Edington, Heywood and Hawkeridge, Coulston, and Upton Scudamore; and in Somerset, Rudge and Standerwick.

Westbury Leigh is sometimes considered a separate village, with its own church and chapel,[29] although it is now a contiguous part of the town.

[33] Businesses at the Brook Lane industrial area, north-west of the railway station, include an Arla creamery which makes Anchor butter.

[34] The West Wilts trading estate, in Heywood parish just north-west of Westbury, has Welton Bibby & Baron who claim to be the UK's largest manufacturer of paper bags and similar goods.

Oldest among them is Ferndale House, now the Conservative Club, just east of the Market Place, which although altered dates from the early 18th century.

[39] In a central position on the Market Place, the early 19th century former town hall is in Bath stone ashlar and has a colonnaded front at street level, behind which shops were inserted in the 1970s.

[40] The Grade II* monument is the Phipps mausoleum in the cemetery, on the Bratton road on the eastern edge of the town.

Dating from around 1871 (for the burial of John Lewis Phipps), the stone monument has a basement, an octagonal chamber with four windows, and a short spire with lantern.

[43] The town is an important junction point on the railway network, as it lies at the point where the Reading to Taunton line, forming a link from London Paddington to Penzance, intersects the Wessex Main Line, linking Bristol and Bath Spa to Salisbury, Southampton, Portsmouth and London Waterloo.

[7] St Mary's Church, Old Dilton was begun in the 14th century but went out of regular use in 1900 after the population dwindled in that area, southwest of Westbury.

[47] The Church of the Holy Saviour at Westbury Leigh was built as a chapel of ease in 1877, the south aisle added in 1889 and the tower in 1890; all in honey coloured limestone, to designs of the Gothic Revival architect William White.

[50][51] There has been a strong Baptist movement at Westbury Leigh, encouraged by the congregations at Southwick, some 4 miles (6 km) away towards Trowbridge.

[56][57] A Methodist church and schoolroom was built in 1926 at the town end of Station Road, replacing a smaller chapel elsewhere dating from around 1809.

The pool was built as a gift to the town of Westbury and opened on Thursday 24th May 1888 in celebration and commemoration of Queen Victoria's Jubilee.

Westbury is served by a fortnightly free newspaper, the White Horse News, named after the defining feature on the edge of the town.