The 13 Colonies

Lore & Background

Long before the 100 touched down, the ground already held its own history. The Skaikru—sometimes called the original Grounders—were the first cohort sent to test Earth's habitability and, in the telling passed down through generations, they were the ones who chose to stay. Their base, a sprawling complex of greenhouses, hydroponic bays, and defensive walls, became the oldest human settlement on the surface. Over the decades that followed, other groups splintered off, migrated, or were driven into the wilderness, and the colonies that emerged each developed their own social structures, spiritual beliefs, and military doctrines.

The Mountain Men carved their identity out of the high passes, trading in weapons and information while keeping their distance from the lowland clans. The Nightbloods, a faction within the Skaikru's broader cultural sphere, embraced a darker theology and a willingness to use the Red Plague as a weapon. The Roanokans and the Ice People represented the geographic extremes—coastal traders and frozen fortress-dwellers, respectively—each convinced their way of life was the only one that could outlast the next catastrophe. The 100's arrival shattered the fragile equilibrium these colonies had maintained, forcing alliances that had been impossible and igniting feuds that had been buried.

What unites the 13 Colonies is not governance or shared law but a common enemy: the knowledge that the Ark, the Barge, and every other ship that once carried humanity are finite. The ground is all there is now, and every colony is a bet that it will be enough.

In Their Own Story

The wind off the ridge tastes like rust and wet stone. Octavia crouches behind a collapsed overpass, counting the Mountain Men's torchlight as it sweeps the valley below. Three. Four. They're not searching for her—they're searching for the Skaikru supply cache, and that means the lowland clans will feel the loss by morning. She presses her back against the concrete, feels the cold seep through her jacket, and thinks about how, a year ago, she was a girl on a metal station learning to weld. Now she's a girl in the dirt, learning to bleed.

Somewhere below, a child is crying. Not a Mountain Man's child—there are no children in the passes. It's a Skaikru kid, maybe eight, lost from the column. Octavia's hand tightens on her knife. She could wait. She could let the torchlight find the kid and be done with it. Or she could go down there, into the dark, and be the thing her mother would never forgive her for being.

The wind shifts. The torchlight swings. She moves.

Reader's Guide

The lowland Skaikru base is the first thing most newcomers see: a broad valley floor ringed by hydroponic towers and defensive palisades, the air thick with the green smell of engineered crops. The walls are old, patched with scavenged metal, and the gatehouse still bears the faded insignia of the original landing cohort. This is the political heart of the colonies, the place where clan disputes are brokered and where the 100 first learned that the ground had rules of its own.

Head north into the high passes and the world narrows. The Mountain Men's territory is all switchbacks and watchtowers, the stone worn smooth by generations of boots. They trade in blades, ammunition, and secrets, and their market stalls are set up in a dry riverbed where the acoustics carry a whisper a mile. You will be watched the moment you cross the first ridge. You will be assessed before you are spoken to.

Further out, the colonies thin. The Roanokan coast is salt and timber, longboats drying on the sand, the smell of rendered fish oil in the air. The Ice People's citadel is a different world entirely: a frozen plateau where the wind never stops, where the buildings are half-buried in permafrost and the only light for weeks is the pale blue of the sky. Each colony has its own rhythm, its own silence. Learn which silence is welcome and which is a warning before the sun goes down.

Did You Know?

• The Skaikru were the first group sent to test Earth's habitability and chose to remain, making them the oldest ground-based settlement in the series.
• The Red Plague, a biological weapon, became one of the central threats to the colonies, reshaping alliances and driving characters to extreme moral choices.
• The Mountain Men operated as a semi-independent trading and mercenary faction in the highland passes, selling weapons and information to multiple clans rather than aligning with any single one.
• The 100's arrival was framed as a test of Earth's viability, but the political machinations on the Ark meant the mission was also a way to offload juvenile offenders from the station.