Ignatius Bonomi (1787–1870) was an English architect and surveyor, with Italian origins by his father, strongly associated with Durham in north-east England.
He was the son of an architect and draughtsman, Joseph Bonomi (1739–1808), who had worked with Robert and James Adam, while his brother Joseph Bonomi the Younger was a noted artist, sculptor and Egyptologist.
Bonomi was Surveyor of Bridges for the County of Durham, and his works included one of the first railway bridges in Britain, over the River Skerne, near Darlington, for the Railway, in 1824 (hence he is sometimes referred to as 'the first railway architect').
He was also responsible for a number of church buildings (including commissions at Durham Cathedral). Other historic buildings, in Gothic and neo-classical styles, included Durham Castle, Lambton Castle (continuing the work started by his father), Durham Prison, Elvet Hill House (1820), Burn Hall,Windlestone Hall and Eggleston Hall, all in County Durham. In Derbyshire he designed Christ Church King Sterndale near Buxton, built in 1848–9 for the Pickford family, founders of the Pickfords removals business.