John Rennie
born  7th June 1761, Phantassie, East Linton, East Lothian, Scotland, UK
baptised  17th June 1761, Prestonkirk, East Lothian, Scotland, UK
died  4th October 1821, Stamford (now Rennie) Street, London, UK
buried  St Paul's Cathedral crypt, London, UK
era  Georgian
A biographical summary
Scotsman John Rennie (senior) dominated the civil engineering profession of his time, with his pioneering ideas and unerring ability to translate them into finished projects. His diverse range of work included bridges, canals, fen drainage, river navigations, docks and harbours. Noted for his thoroughness, he was frequently called upon to adjudicate on the design work of his contemporaries.
As a boy Rennie was fascinated by machinery, and at the age of 12 he began working for millwright Andrew Meikle (1719-1811). Six years later, Rennie established his own millwrighting business and went on to combine a growing workload with academic studies at Edinburgh University.
In 1783, he met James Watt (1736-1819), who later offered him a contract for the installation of Boulton & Watt steam engines, including those at Albion Mills in London, designed by Samuel Wyatt (1737-1807). This project established Rennie's reputation. Wherever motive power was needed, he had an idea for using steam — in mills of all kinds, smithies, ships and even in London's Royal Mint.
Rennie's focus moved to civil engineering when he began working on canals, with the backing of an endorsement from inspirational engineer John Smeaton (1724-92). The bridge-building for which he is best remembered started with masonry structures over these canals. Towards the end of his career, he designed the granite London Bridge (1831) that was later famously purchased by American businessmen and re-erected in the Arizona desert.
He also designed iron bridges — then a developing technology. In fact, Britain's longest cast iron span was part of Rennie's Southwark Bridge (1819), of which he said, "On the whole nothing in which I have ever been concerned has proved more satisfactory than this bridge".
Rennie's habitual attention to detail and heavy workload drove him to work 12-15 hours a day. He built things to last, which sometimes led to criticism of his work on grounds of size or cost. However, his expertise was recognised by promoters, who knew his name would lend authority to any scheme with which he was associated.
He was invited by Smeaton to join the Society of Civil Engineers (founded 1771, later renamed the Smeatonian Society) and he became a Fellow of the Royal Society, though he declined the knighthood offered for his work on the original Waterloo Bridge. Among his nine children are engineers George Rennie (17911866) and Sir John Rennie (17941874), both of whom would hold office as presidents of the Smeatonian Society.
Rennie, a lifelong Presbyterian, is described as charming and determined — a man who maintained friendships despite a somewhat short temper. He was one of the greatest civil engineers of his era, and it is a shame how few of his structures remain to remind us of his genius.
1761 Born 7th June, ninth and youngest child (three brothers, five sisters) of farmer and brewery owner James Rennie (c.1715-66) and Jean Rennie (1729-90)
1773 Works for millwright Andrew Meikle (1719-1811), learning the practicalities of mechanics
1775-7 Attends Dunbar secondary school
1779 Sets up his own millwright business
1780-3 Studies natural philosophy and practical sciences at University of Edinburgh, where he meets Joseph Black (1728-1799) and John Robison (1739-1805)
1783 Study tour of England, meets James Watt (1736-1819), who later (1784) offers him a contract for installing Boulton & Watt steam engines
1790 Marries Martha Ann Mackintosh (1771-1806), 6th November at Christchurch, Blackfriars Road, Southwark (nine children)
1790 Appointed Surveyor to the Kennet & Avon Canal (built 1794-1810)
1791 Appointed Surveyor/Engineer to the Rochdale Canal (built 1794-1804)
1798 Elected Fellow of the Royal Society
1817 Declines a knighthood
1821 Dies of liver disease, 4th October, at his residence in Stamford Street (London), interred in the crypt of St Paul's Cathedral
Selected works
Lancaster Canal, Lancashire, UK .... begun 1792
Lune Aqueduct, Lancashire, UK .... 1794-1796
Great Bedwyn Skew Bridge, Wiltshire, UK .... 1794-1816
Leith Docks, Leith, Edinburgh, UK .... begun 1800
Kelso Bridge, Borders, Scotland, UK .... 1801-1804
Devizes Locks, Kennet & Avon Canal, Wiltshire, UK .... opened 1810
Plymouth Breakwater, Devon, UK .... begun 1812
Old Waterloo Bridge, London, UK .... 1811-1817
Sheerness Dockyard, Isle of Sheppey, Kent, UK .... 1813-1821
Old Southwark Bridge, London, UK .... 1815-1819
Kingstown Harbour, County Dublin, Ireland .... 1817-1821, completed 1836
London Bridge (1831), London, UK .... designed 1821, built 1824-1831
All items by John Rennie
Everything built ... 1761 - 1821
Rennie, John (1761-1821), Dictionary of National Biography,
Smith Elder & Co, London, 1885-1900
Andrew Saint, Rennie, John (1761-1821), Oxford Dictionary of National Biography, Oxford University Press, 2004, online edn May 2009
Alec Skempton ed., Rennie, John, FRS, FRSE (1761-1821), A Biographical Dictionary of Civil Engineers in Great Britain and Ireland, Volume 1: 1500-1830, Thomas Telford Publishing Limited, Institution of Civil Engineers, London, pp.554569
Further reading
GB 237 Coll-168, archive of letters written by John Rennie held at Edinburgh University Library, Edinburgh, Scotland, UK
John Rennie 1761-1821 / John Rennie 250, guide to exhibition at the Institution of Civil Engineers, London, 2011, available at
Barry M.J. Barton, John Rennie and the drainage of the Witham Fens, Lincolnshire, UK, Proceedings of the ICE: Engineering History and Heritage, Vol.164, 1st Aug 2011, pp.175-187
Cyril Thomas Goodman Boucher, John Rennie, 1761-1821: The Life and Work of a Great Engineer, Manchester University Press, 1963
Mike Clarke, John Rennie and the Rochdale Canal, UK, Proceedings of the ICE: Engineering History and Heritage, Vol.164, 1st Aug 2011, pp.143-154
Peter S.M. Cross-Rudkin, John Rennie and his resident engineers, Proceedings of the ICE: Engineering History and Heritage, Vol.164, 1st Aug 2011, pp.189-196
Richard L. Hills, John Rennie, mechanical engineer, Proceedings of the ICE: Engineering History and Heritage, Vol.164, 1st Aug 2011, pp.131-141
Roland Paxton ed., John Rennie (1761-1821), FRSE, FRS, civil engineer: Contemporary biographical notices reprinted on the 250th Anniversary of his birth, Heriot Watt University, Edinburgh, 2011
Ted Ruddock, John Rennie and Waterloo Bridge, London, UK, Proceedings of the ICE: Engineering History and Heritage, Vol.164, 1st Aug 2011, pp.155-162
Samuel Smiles, Lives of the Engineers, Volume 2, John Murray, London, 1862
Tom Swailes, Southwark iron bridge, London, UK, Proceedings of the ICE: Engineering History and Heritage, Vol.164, 1st Aug 2011, pp.163-173
portrait  John Rennie by George Dance, pencil, 1803, NPG 1154
© National Portrait Gallery, London

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John Rennie
© 2022 Engineering Timelines
Extract from the birth register
John Rennie was the ninth child of
James Rennie — a modest Scottish tenant farmer and brewery owner — and his wife Jean. James died relatively young, leaving eldest son George to lead the family at 17 years old. John attended the local parish school until he was 12.
Birth register: Crown copyright
Extract from the 1780 marriage index
In 1790, John Rennie married Martha Ann Mackintosh at Christchurch in Blackfriar's Road, Southwark (London). They would have nine children, two of whom would become
well-known engineers.
Marriage record: Pallot's Marriage Index 1780-1837
Devizes Locks
There are 29 locks in the Devizes area of Wiltshire on the Kennet & Avon Canal, for which Rennie was appointed surveyor in 1790. The Caen Hill section of the Devizes Locks shown above is an impressive run of 16 brick-lined lock basins.
Photo: © John Sparshatt and licensed for reuse under this Creative Commons Licence
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Southwark Bridge by P. Noel Boxer
The original Southwark Bridge across the River Thames in London, designed by John Rennie and completed in 1819. Its centre arch spanned 73m, making it the longest cast iron span in the country
at the time.
Drawing: Southwark Bridge by P. Noel Boxer, University of Toronto and the Internet Archive, courtesy The Victorian Web
Kelso Bridge, River Tweed
The handsome Kelso Bridge on the River Tweed — a precurser to Rennie's Waterloo and London bridges. Kelso was designed in 1799 and completed in 1804. Two lamp standards removed during the 1936 demolition of Waterloo Bridge are installed here.
Photo: © frank smith and licensed for reuse under this Creative Commons Licence
London Bridge, circa 1902-6
Looking north over Rennie's five-arch masonry London Bridge (1831), the successor to the 600 year-old Old London Bridge. Rennie's design was submitted for consideration by his sons after his death, and was completed under the supervision one of them, noted engineer Sir John Rennie.
Photo: anonymous, circa 1902-6, courtesy The Victorian Web