William Henry Clayton (17 November 1823 – 23 August 1877) was a Tasmanian-born colonial architect who practised initially in Tasmania and then in New Zealand.

William was born on 17 November 1823, in a house called Wickford at Norfolk Plains, Australia, one of the 13 children of Mary (nee McLaughlan) and Henry Clayton.

[2] At the age of 16 Henry received a land grant in Tasmania, which enabled him to become a prosperous businessman by the time his son William was born.

[4] William was educated at the local exclusive Longford Hall Academy, where he won prizes in geography, French, Latin and mathematics.

[5] As Henry Clayton wanted his son to have the benefits of higher education, the family moved to England, departing on 28 March 1840 on the Adelaide.

William furthered his education by being articled to a prominent architect, and received training in architecture, civil engineering and surveying.

[7] The Public Building in Launceston (1860), which was constructed of brick with richly-modelled freestone dressings and Italianate classical in style, was the most ambitious and lavish of his secular works.

[8] Clayton was a member of the Royal Victorian Institute of Architects, Melbourne, served as a Launceston Alderman from 1857 to 1863, and was appointed a justice of the peace in 1858.

While Mason was involved in the selection of the site it was Clayton who eventually took the lead role with his design being preferred by the Premier, Frederick Weld.

[8] Clayton's appointment coincided with the start of the extensive public work schemes of his son-in-law Julius Vogel who became colonial treasurer in June 1969 and was Premier from 1873 to 1875.

[5] In carrying out his duties Clayton travelled widely, visiting Auckland, Tauranga, Gisborne, Napier and Nelson in 1875, and undertaking a major tour of the South Island in 1876.

While in Dunedin his old ankle injury gave trouble and an abscess developed which became so infected that Dr Thomas Hocken, who was attending him, strongly advised amputation.

[12] His wife, Emily who was in England visiting their daughter Mary Vogel at the time of his death returned to New Zealand to settle her husband's estate.

[11][5] Following Clayton's death, his chief draughtsman Pierre Finch Martineau Burrows took over running of the office, though he was never appointed to the position of Colonial Architect.