Muckle Skerry is the largest of the Pentland Skerries that lie off the north coast of Scotland. It is home to the Pentland Skerries Lighthouse.

Muckle Skerry lies in the Pentland Firth at grid reference ND464782. It is the westernmost of the skerries. At one kilometre (five furlongs) long and rising to an elevation of 20 metres (65 feet) above sea level, it is sizable enough to be considered an island. However, the notoriously bad weather of the firth has historically rendered Muckle Skerry uninhabitable and as such it is more often thought of as a skerry.

The skerry is part of the Pentland Firth Islands Important Bird Area (IBA), so designated by BirdLife International because it supports significant breeding populations of seabirds.^[3]

Pentland Skerries Lighthouse was constructed in 1794 by the Commissioners of the Northern Lights. The engineers were Thomas Smith and his stepson Robert Stevenson (this was the first light that Stevenson officially worked on).

• List of lighthouses in Scotland
• List of Northern Lighthouse Board lighthouses

• Pentland Skerries Northern Lighthouse Board
• Northern Lighthouse Board

58°41′18″N 2°55′35″W / 58.68824°N 2.92631°W / 58.68824; -2.92631