The Water of Leith is the main river flowing through Edinburgh, Scotland, to the port of Leith where it flows into the sea via the Firth of Forth. It is 35 km (24 miles) long and rises in the Colzium Springs at Millstone Rig of the Pentland Hills. Along the river there were many mills. The 18th Century brought substantial development to this area, with many new flax, snuff and paper mills springing up around the Water of Leith. These mills were a prominent feature of village life until fairly recently.