Thomas Blashill (c.1831-20 January 1905) was an architect. Born in Yorkshire, he moved to London and trained as an architect. In 1876 he was appointed District Surveyor for Bethnal Green East by the Metropolitan Board of Works. In 1886 he was promoted to the of Superintending Architect of Metropolitan Buildings and Architect and Superintending Architect of the Board. When the board was abolished in 1889 and replaced by the London County Council he became Superintending Architect of Metropolitan Buildings and Architect to the Council. He was responsible for designing the Old County Hall, Spring Gardens, the Boundary Estate, the Millbank Estate and the entrances for the Blackwall Tunnel.