Rennie was born in East Linton, Scotland, in 1761. After working
as a millwright with Andrew Meikle he studied at Edinburgh University
(1780-83). He was employed by Boulton & Watt for five years
but in 1791 he moved to London where he started his own engineering
company. Over the next few years he became a famous bridge-builder.
This included Leeds Bridge, Southwark Bridge and Waterloo Bridge.
also responsible for designing and building docks at Hull, Liverpool,
Greenock and Leith and improving the harbours and dockyards
at Portsmouth, Chatham and Plymouth. Rennie's last project was
London Bridge but it was unfinished when he died in 1821. The
bridge was completed by his son, John Rennie.