Underland is the subterranean world beneath Narnia: a country of underground seas, dimly lit roads, and kingdoms concealed below the surface. Its geography both enables the Lady of the Green Kirtle’s plan to invade the Overworld and makes escape dangerous. Once the Witch is killed, the magic sustaining her kingdom ends; the resulting collapse turns the hidden realm into a race against flood, darkness, and closing rock.

Definition and Setting

The travelers’ first view of the marsh country above Underland establishes the contrast between surface and depth. The plain is divided into countless small islands by channels of water, bordered with reeds and rushes, and occupied by scattered wigwams. It is lonely but, in morning sunlight and fresh wind, also open and invigorating. The route northward leaves this marshland behind for increasingly severe country: narrow valleys exposed to a cold wind, stony ground, and then a flat, storm-lashed hill crossed by banks or dykes. These successive landscapes make the descent into Underland feel like the culmination of a difficult journey rather than a sudden change of scene.

Below ground, light and visibility contract. On the Sunless Sea, a pale lantern illuminates only a short distance; ahead, the travelers see smooth dark water giving way to absolute blackness. The boat carries them beneath the Ruined City, returning them to the route prescribed by their instructions. Underland is therefore not merely an unknown space below Narnia: it is the place where the quest’s signs regain their practical force after the travelers have been diverted from them.

Hidden Route and Invasion Plan

Prince Rilian knows that several outlets lead from Underland to the surface. He has been taken through many of them, but always in the Witch’s company and after traveling by ship across the Sunless Sea. That history leaves him uncertain whether the underground inhabitants would let him reach a harbor and depart with four strangers without asking questions.

The more urgent route is the Witch’s new excavation, intended as an outlet for an invasion of the Overworld. It lies on the travelers’ side of the sea, only a few miles away, and is nearly complete: at most, only a few feet of earth separate the diggings from open air. The plan gives Underland a political purpose as well as a geography. The Witch intends to emerge beneath Narnia and rule it through Rilian, while keeping him unaware that the country she would make him king of is his own. He would be king in name but her slave in fact.

The older Beasts and Dwarfs later understand the scale of the plot: the Witch had killed Rilian’s mother, enchanted the prince, and dug beneath Narnia to prepare her attack. They connect her scheme with the dangerous giants of Harfang and compare her to the White Witch, who had brought the Great Winter on Narnia. Underland’s hidden route thus links the prince’s personal captivity to a larger attempt at conquest.

Collapse of the Deep Lands

After the travelers kill the Lady of the Green Kirtle, they discover that her kingdom is tied to her magic. Ships are driven out of the harbor and into the city streets as the sea rises. Rilian recognizes the cause: when the Witch’s head was struck off, that blow ended her magical works, and the Deep Lands began to fall apart. Her death does not simply remove the ruler of Underland; it releases the forces that had held her realm together.

The collapse also changes the lives of the underground inhabitants. Golg explains that the gnomes had been working under the Witch’s control, silent and burdened for years. When the great crash comes, they recognize that they have been enchanted, abandon their loads and tools, and turn toward a red glow rising from a crack into the Really Deep Land, a thousand fathoms below. As the chasm begins to close, the gnomes hurry back through it. Their departure makes the destruction more than a royal crisis: the Witch’s defeat breaks her hold over the workers of her kingdom and opens their way home.

The travelers’ own escape depends on reading the changing landscape quickly. After the chasm closes, the lamps still mark a road through an Underland that has become darker and drearier. They ride downhill toward moving water, then cross a valley where the rising tide is already running fast. It reaches only a foot or two above the ground at the crossing, but the horses have little margin for safety. Behind them, the hills become islands and distant lamps disappear as water spreads through the lowlands. The road remains visible for a time, while the route behind them is progressively submerged.

Significance and Aftermath

Underland’s defining reversal is that the route intended to carry an invasion into Narnia becomes the setting of the Witch’s defeat and the danger the rescued travelers must flee. The underground world begins as a concealed passage into the surface kingdom, but its dependence on the Witch’s enchantments makes it unstable once her power ends. The rising sea, vanishing lamps, and closing chasm translate the collapse of her rule into immediate obstacles to survival.

The realm also brings the quest’s dispersed evidence together. Above ground, the travelers have been tempted by the comforts promised at Harfang and have lost sight of the search and its instructions. Beneath the Ruined City, they recognize that they have returned to the right path. In Underland, Rilian’s identity and captivity become clear, the invasion plan is exposed, and the Witch’s death releases both the gnomes and the land she had controlled. The escape from the collapsing realm is therefore at once a physical return from the depths and the final consequence of dismantling the hidden power directed against Narnia.