Thomas Sopwith was born in January 1803 in Newcastle upon Tyne. His father, Jacob Sopwith was a cabinet maker and initially Sopwith trained in his father's business. From an early age he had been interested in drawing and design and he began to study land-surveying, taking on projects such as the construction of a prison in Newcastle upon Tyne and later working for Joseph Dickson of Alston, with whom he went into partnership in 1825.
Sopwith was mainly involved in surveys of mines, but he also worked on some of the early railway surveys, in England, Belgium and in France, taking on commissions as they were offered to him. He became one of the choice engineers for some of the main projects taking place at the time and was involved in various schemes including the Newcastle and Carlisle railway, railway surveys in County Durham, the survey of the mines in the Forest of Dean, Gloucestershire and the road from Newcastle to Otterburn.
In 1845 he became chief agent for W.B.Lead Mines based at Allenheads (otherwise known as the Blackett-Beaumont Company or simply the Beaumont Company) which mined lead in Allendale and in Weardale. In the same year he was elected a Fellow of the Royal Society of London.
Sopwith's interests, however, did not just lie in engineering. He researched and wrote on antiquity in Northumberland, social concerns, architecture, geology, and technical drawing, often illustrating works with his own engravings. Whilst chief agent at Allenheads he was personally involved with improvements for the poor and workers of the area - designing better living spaces, improving conditions such as education, and introducing libraries and benefit societies.
He remained in Allenheads until his retirement in 1871, at which point he withdrew from all professional life and moved to London where he lived out his retirement, punctuated by excursions abroad, until his death on 16 January 1879. He was well known by fellow scientists and the diaries include descriptions of meeting with many eminent men and women.
He received an honorary M.A. from the University of Durham in 1857.
He was married three times, initially to Mary Dickenson of Alston in 1828, to Jane Scott of Ross, Northumberland in 1831 and finally to Anne Potter of Newcastle upon Tyne in 1858.
Sopwith wrote many pamphlets and publications, including; A historical and descriptive account of All Saints' church in Newcastle upon Tyne (1826); An account of the mining districts of Alston Moor, Weardale and Teesdale in Cumberland and Durham ... (1833); A treatise on isometrical drawing as applicable to geological and mining plans ... (1838); The award of the Dean Forest mining commissioners ... (1841); On the practical importance of meteorology ... (1859)