The Union Canal, with today's length of , was built as a contour canal, following the contour throughout its length, thereby avoiding the delay due to locks, at the expense of some prodigious civil engineering structures.
The canal has several navigable aqueducts, including the Slateford Aqueduct that takes the canal over the Water of Leith in Edinburgh, the Almond Aqueduct near Ratho and the Avon Aqueduct near Linlithgow, the second longest in the United Kingdom.