Untill
From Warhammer 40k - Lexicanum
The Untill is a vast marshland on the planet Gereon, so named because the earliest colonist's maps marked the regions as unsuitable for farming or 'Untillable'.[1] It covers approximately 900,000 square kilometres.
Its flora and fauna are largely poisonous. The most notable native lifeform is a large species of moth.
The Untill is home to the Partisans, tribal inhabitants who resisted both Imperial and Chaos rule, though they sided with the Imperium against Chaos after being recruited by Ibram Gaunt.