William Tierney Clark FRS FRAS[1] (23 August 1783 – 22 September 1852) was an English civil engineer particularly associated with the design and construction of bridges.

Tierney Clark is also credited with the design of a tunnel between Higham and Frindsbury, near Rochester in north Kent for the Thames and Medway Canal.

The canal was not a success but the tunnel was acquired in 1846 and adapted in 1847 for use by the South Eastern Railway for its North Kent Line route between Gravesend and Rochester.

His memorial in the local parish church, St Paul’s, shows an outline of his design for the nearby bridge.

His bridge has since been replaced by a later one designed by Sir Joseph Bazalgette, which reuses the Tierney Clark pier foundations.