When hobgoblins have the time and drive to construct their own domiciles and fortresses they invariably make use of hills both natural and hob built. Trees will be cleared and undergrowth kept low sometimes as far as three bowshots from a hills base. The hills will be hollowed out to house halls and tunnels and surfaces dotted with defensive works.
The basic Hobgoblin edifice is an earth-lodge large enough to support a squad or even and entire cohort of hobgoblin warriors. A freshly built Hob-barracks will be dug into the ground almost an entire story with a sturdy well supported roof.
Hobgoblins will pile their midden upon the roofs of a hob-barracks. There are a number of reasons for this which include discouraging squeamish folk from trying to dig into a hob-barracks. A degree of warmth is added by the decomposition of the midden.They encourage the growth of fungus which hobgoblins gain more greater nutrition from than do men and hob-goblin youth gain vital weapons practice keeping the vermin population in check a-top their barracks-middens.
Overtime a hill will grow atop a barracks and be overgrown with a good an well nourished growth of sod. This growth will diminish the impact of initial fire-based attacks on the Hob-Barracks.
A Barracks will typically have one or two commonly used entrances. These entrances will be guarded by exterior and interior walls to discourage assault and break line-of sight to ward off the impact of hostile magic-users.
There will be many small ports that allow for ventilation and smoke to escape. The channels for these ports zig-zag to break a line of effect.
Inside the Hob-Barracks there is little privacy and areas will be blocked off by all manner of screens. A main hearth will warm the whole structure. Some storage will be dug beneath the barracks floor here and there. Older barracks will have small tunnels and chambers built in the midden hill above that can only ideally be entered from within the barracks.
A small structure not unlike the barracks but built to monitor a point of approach. bunkers will have one or more guarded firing/observation points and the means to house a squad of Hobgoblin warriors. It's not uncommon for the bunk-space in a bunker to be completely separate from firing/observation points with perhaps only a communication port between the two chambers. The main entrance to a bunker will be fortified with a heavy door or small gate and an entrance to larger bunker will certainly be defended by murder holes.
A large subterranean communal hall where the chieftain can oversee and instruct a large number of the tribe at one time. This hall is often built deep into the center of a hill and can only be entered after traveling through a number of subterranean tunnels. These tunnels will be monitored by guard chambers and murder-holes. entry tunnels typically enter into the main-hall from a stair beneath the level of the hall floor, thus providing a last defensive point for hobgoblins above any who would invade the hall.
The hall itself will be simple or complex as the commanding chieftain wishes it to be. There will be a number of ante-chambers and galleries off the main hall that contain living space, storage space and defensive points for a chieftain and his guard. Storage space will typically be in subterranean chambers accessible only by passages leaving the main hall proper.
An hob-hall is often surrounded by a series of trenches which allow a degree of defense to troops but aren't as vulnerable (or expensive) as walls. These trenches will have sleeping space and may-haps bunkers to protect them or a lien of trench.
With the exception of a communication trench here and there a hob-trench seldom runs straight for more then 40'.
Trenches are ideally constructed to allow observation from further up-hill and in threat of fire from those guarding the hill while protecting agaisnt fire from those approaching from outside the hob-hill.
A common defense of hob-trencheds is a number of ankle-biters concealed beneath boards at the bottom of trenches. When hobgoblins are forced to leave the trenches or leaving for a while on expedition they will pull the boards away exposing the ankle-biters.
Hobgoblin engineers are endlessly tinkering with and innovating trench-works so the variety of features can vary greatly from hob-hill to hob-hill.
Very shallow trenches or pits, sometimes concealed, with a number of spikes positioned so as to trap and maim the foot and leg of an unwary trespasser who treads upon one.
These are but a common example of the large number of stakes, hedgehogs, dead-falls and related mantraps hobgoblins will encircle themselves with.
A simple four posted tower with a sheltered observation/firing platform. the most curious feature of a Hob-towers is they will often be built in close proximity to a twin with a narrow bridge between-the two that allows travel without having to climb down. Often only one of the two towers offers comfortable access to the ground and this will be exposed to the twin.
Such towers will only be built atop fairly young hob-hills. As the works become more established the towers will be built further downhill and away from the center so they don't' serve as useful points of capture for an invading force.
These towers are always built of wood so they can be set afire if they prove to aid attackers attempting to overrun the hill.
It not uncommon for well established Hobhills to be surrounded by moats. Sometimes trenches are flooded and turned into moats (this isn't always the initial intent of the builders).
Hobgoblins will use boats and even have raft-like firing platforms in particularly wide sections. some hob-hills can only be accessed by travel upon the moats (with the exception of few concealed and very deep tunnels).
Moats will have draw-bridges and wobble-walks to aid in defense of the hill. It isn't uncommon for shallow moats to have stakes and ankle-biters in their depths.
A simple layout of easily deconstructed bridgeways that allow precarious and seemingly haphazard travel over moats, trenches and other defenses. They often require one to walk on a single beam and steady themselves with a hand on a second beam or guide rope. Difficult to reach accesses to hob-place may have a dozen or more wobble walks leading to them and away that can be quickly removed in times of danger.
A hob-hill will often be protected by a number of walls. These walls are often simple visual screens meant to block rapid assault and missile fire they are not the large and encircling walls of mannish castles. Hob walls may have firing ports but seldom have any form of defenses along their tops. It's not uncommon for the base of a wall to have a hedge-hog of spikes facing the approach.
Some hobgoblins aware of how men build castles will build walls in a manner to channel invading mannish troops into a dead-end killing space.
These are large fortress/towns of Hobgoblins. They will be a number of hill spiraling our from a central commanding hill or rings of hob-built hills surrounding the hill of the warlord in command of the place.
Hobgoblin Citadels are difficult to attack as they don't allow for easy travel of unfamiliar troops, are not friendly to mounts and offer poor targets to siege weapons. Even spell-casters will have difficulty ensuring all but the mightiest magic have effect as hobgoblins are aware of the basic limitations of line-of sight and area of effect inherent in many popular combat spells.
Orcs enjoy taking over established Hobgoblin citadels (when chance allows it) but it is easy to tell orcs have over-run such places as moats will dry-out, trenches will be poorly maintained and sanitation will degrade as hills are opened by pits for orcish industry and towers and walls are toppled and burnt for fuel or rebuilt in orcish patterns. Orcs surprisingly enough turn up their noses at hobgoblin midden practices and it isn't unusual for a hob-barracks to be forgotten and lost under a pile of orcish refuse.