Nor Loch

The Nor Loch, also known as the Nor' Loch and the North Loch, was a loch formerly in Edinburgh, Scotland, in the area now occupied by Princes Street Gardens, which lies between the Royal Mile and Princes Street.

The depression, along with the parallel one, now occupied by the Cowgate, was formed by glacial erosion during the last Ice Age, when the icepack was forced to divide by the volcanic plug now known as Castle Rock.

The Nor Loch was initially a marsh, and part of the natural defence of the Edinburgh Old Town. Because the Old Town was built on a steep ridge (still clearly visible today), it expanded on an east-west axis, eastwards from the castle; expansion northward, as would happen with the later New Town, was extremely difficult at this point. The Nor Loch was thus a hindrance to both invaders and town growth.

In 1460 King James III ordered the hollow to be flooded in order to strengthen the castle's defences. The loch was formed by creating an earthen dam to block the progress of a stream that ran along the north side of the castle. The water level was controlled by sluice in the dam. It is thought never to have been particularly deep.

In the winter of 1571, the Earl of Morton suggested an English army would more easily capture the Castle from the north because the Loch would be frozen and there were no town walls on that side.

In 1603, King James VI gave the Town Council title to the land, pools and marshes of the loch.

As the Old Town became ever more crowded during the Middle Ages, the Nor Loch became similarly polluted, by sewage, household waste, and general detritus thrown down the hillside. Historians are divided on whether the loch was ever used for drinking water.

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