Though born in London, Ignatius Bonomi based his practice in Durham. He and his friend John Dobson (q.v.) were the only professional architects, as opposed to builder-architects between York and Edinburgh. Between them they dominated the architectural scene in the first half of the nineteenth century, working in all manner of styles and on all types of building.

Bonomi's masterpiece was Burn Hall, just south of Durham, but he also worked at Lambton Castle and may well have designed the Edens' mansion, Windlestone Hall. The Durham Crown Courts and gaol are mainly Bonomi's design of 1811 and he worked on Durham cathedral too, refacing the south front with fine sandstone ashlar.
Elvet Hill in Durham is a Tudor-gothic house built by Bonomi for himself (now the School of Oriental Studies). It connects with the famous Gulbenkian Museum of Oriental art. In Middleton-in-Teesdale, a classical arch in Masterman Place leads to New Town, with company houses of 1823-24 by Bonomi for twenty-five miners and two overseers. Bonomi also built the steam-locomotive bridge in Darlington in 1825.
Dinsdale Park school was designed by Bonomi for Lord Durham in 1829 as a seventy-room hotel with seven acres of pleasure grounds 'for seclusion and medical treatment' connected with the short-lived spa (a sulphur well had been found in 1789). Ignatius Bonomi also supervised the rebuilding of the magnificent mansion Wynyard Park, after the fire of 1841.