Ettinsmoor (derived from Ettins' Moor) was the Giant-inhabited land directly to the north of the Kingdom of Narnia, west of the Bight of Calormen, east of the Western Wild region, south of the Wild Lands of the North, bordered on the south by the River Shribble, and on the north by the Great Northern River. To the west it was bordered by the western mountains, and to the east of the Merpeople's sea nation by the Eastern Ocean. It is the only official nation (as recognised by the Kingdom of Narnia) in the Wild Lands of the North.
The country was a rough and stony moor, traversed by many streams and rivers. Wild geese commonly flew over Ettinsmoor in the late autumn.
The Ettins were once a sophisticated species of Giants that built ancient cities and bridges in Ettinsmoor and their Giant neighbour country, the Wild Lands of the North during the Age of Conquest. However, some time during the Age of Winter, the Giants became uncivilised at best. The inhabitants of Ettinsmoor became notorious for their stupidity and vicious temperament. Physically, they resembled rock formations when standing still, helping them to blend into their barren surroundings.
With this in mind, it is possible that the reason why the Giants were once sophiscated is because they may have been ruled by Jadis the White Witch. When she first came to Narnia, she was banished to the north, where she remained for 900 years. It is possible that during that time she ruled the Giants, and got them to build the ancient city that now lies in ruins. After she eventually returned to and conquered Narnia, she most likely left the Giants in their own country where, without her guidance, the Giants degenerated into their brutish selves.
The northern Giants regularly waged unofficial war with their southern neighbors in Narnia for many years into the Golden Age. The High King Peter, during a northern expedition, finally declared war on the eastern side of the nation by recognising it as its own independent nation, Ettinsmoor (having been a previously unnamed region). He defeated the Giants in the Ettinsmoor War in the Narnian-year 1014, and with this, they were forced into constructing Ettinsmoor as a new, united nation as part of the Narnian Empire, in which the River Shribble was its northern fronier. The Ettin inhabitants, however, were unable to establish for themselves a long-standing political system, and continued their savage and anarchical lifestyles, and during the second half of Narnia's Dark Age, the east side of the nation succussfully fought for independence and ceased to be part of the empire since Narnia itself was in anarchy.
During the Telmarine era it was largely left ignored, but it was apparently under control by Telmarine armies. Telmarine settlers settled in some areas of the southern part of the area.
In the Age of Exploration, the Ettins were again encroaching on Narnian territory in the time of Caspian X, who defeated them in 2304, and forced them to pay tribute. At this point, the east of Ettinsmoor was reincorporated into the Narnian Empire as the Barony of Ettinsmoor, a new Narnian territory. However, some time during the Later Ages, outlaws of various species from Narnia rebelled, but were defeated and exiled from Narnia, and took refuge in the west of Ettinsmoor.
By 2534, king Erlian's father built three guard towers in the Lantern Waste, to prevent Narnia from being attacked from unofficial northern invaders. When they did attack, the insurgent army suffered a major blow, but at the cost of many Narnian solders and Erlian himself, as well as the latter's leader, who was a Giant. Tirian soon took his father's place, and lead an army on the west of Ettinsmoor, conquered the region for the Narnian Empire, and crushed the recovering rebellion.
- Ettinsmoor is spelt as "Ettinsmoor" in The Silver Chair, but as "Ettinsmuir" in The Last Battle. Both are acceptable spellings.
- The word Ettin is an obsolete form of the word eten (meaning giant), and a "moor" is a high and open wasteland.
- "Ettenmoors" is the name of a region in Middle-earth, also inhabited by Giants. The reason for this would likely be the close friendship between Tolkien and Lewis.
- Paul F. Ford, The Companion to Narnia (San Francisco, 1994)