Located in the system of sewerage and other tunnels beneath New York, the Morlock Tunnels were home to close on fifty homeless mutants who names themselves 'Morlocks' after the subterranean dwellers of H.G. Wells' The Time Machine. In a series of cul de sacs, natural caves and abandoned storage facilities, the mutants made their dwellings, stealing or scrounging what they needed from the 'surface world' what they needed to survive.
Following the Morlock Massacre, the bodies of those slain remained unburied in the tunnels. It was among this rather grisly company that Sarah Morlocke made her home for several years, upon returning to the tunnels to find her 'family' dead. It was also the scene, nearly a year later, of Sarah's near-death at the hands of the Marauders.