The map printed as part of Part II of Gulliver's Travels appears to indicate that Brobdingnag is located on the northwest coast of California. In the book Gulliver describes how the ship reached a latitude of five degrees south, northward of Madagascar before it is blown by strong winds "a little to the east of the Molucca Islands, and about three degrees northwards of the line [equator]. From there the ship is driven by a storm "about five hundred leagues to the east". Lemuel Gulliver claims to have discovered the land in 1703.
Brobdingnag is a continent-sized peninsula six thousand miles long and three thousand miles wide, which based on the latitude and longitude given by Gulliver just before he shipwrecks there, would suggests it covers all of Alaska, the Yukon, the Bering Sea, and a small section of eastern Siberia. Brobdingnag has a range of volcanoes up to 30 miles (48 km) high separates the country from unknown land to the northeast, and Brobdingnagians have never been able to develop ocean-going ships. Lorbrulgrud is claimed to be the capital with the king having a seaside palace at Flanflasnic.
Brobdingnagians are described as giants who are as tall as a church steeple and whose stride is ten yards. All of the other animals and plants, and even natural features such as rivers and even hail, are in proportion. The rats are the size of large dogs and the flies are the size of birds. This also means that the country is far more dangerous for people of our size, as evidenced by Gulliver using his sword far more often here,namely, on attacking vermin than in any other of the strange countries he visited; fortunately for Gulliver, the people are civilized. Fossil records are claimed to show that the ancestors of the Brobdingnagians were once even larger. The King of Brobdingnag argues that the race has deteriorated.
Gulliver relates that, in the past, there were battles between the monarchy, nobility, and people resulting in a number of civil wars ending in a treaty. The monarchy is based on reason. The King of Brobdingnag finds European institutions and behaviour wanting in comparison with his country's. Based on Gulliver's descriptions of their behaviour, the King describes Europeans as "the most pernicious race of little odious vermin that nature ever suffered to crawl upon the surface of the earth."
Swift intended the moral relationship between Europeans and Brobdingnagians to be as disproportionate as the physical relationship. The King of Brobdingnag is considered to be based on Sir William Steele, a statesman and writer, whom Swift worked for early in his career.
The learning of tBrobdingnagians is very defective, consisting only in morality, history, poetry, and mathematics, wherein they must be allowed to excel. But the last of these is wholly applied to what may be useful in life, to the improvement of agriculture, and all mechanical arts.Gulliver was unsuccessful in explaining to them any conceptions of ideas, entities, abstractions, and transcendentals.
Gulliver finds that no law of that country must exceed in words the number of letters in their alphabet, which consists of twenty two. And only a few of them extend even to that length. They are expressed in the most plain and simple terms. Those people are not spirited enough to discover more than one interpretation. To write a comment upon any law is a capital crime. As to the decision of civil causes, or proceedings against criminals, their precedents are so few, that they have little reason to boast of any extraordinary skill in either.
The army of Brobdingnag is claimed to be large with 207,000 troops including 32,000 cavalry although the society has no known enemies. The local nobility commands the forces; firearms and gunpowder are unknown to them. The King castigates Gulliver when he tries to interest the statesman in the use of gunpowder.