The Sea of Swords separates the western coast of Faerun from the Nelanther Isles, the Moonshaes, Evermeet, Lantan and the further off areas of Abeir-Toril such as Maztica. The famed explorer Balduran was the first noted Faerunian to explore the sea extensively, returning with wealth enough to build a huge city, a fine ship and with enough left over to retire comfortably.
The sea is named for its numerous pirate attacks upon the shipping route extending from Waterdeep in the north, to Calimshan in the south. Piracy in the region is rampant despite the efforts of the navies of various Sword Coast ports and pirate hunters.
Whereon it can be seen that there's a large offshore island situated so that its northern shore is due west of Candlekeep. Directly to the south of this island is an east-west line of three small islands, and northwest of this same large island are another three islands, curving (bulge to the west) in an arc to the northwest.
All seven of these islands are high and rocky (cracked and fissured granite), and covered with scrub temperate woodlands. With one exception, their heights are windswept rock whitecapped with guano, and they are all primarily inhabited by thousands of seabirds. There are freshwater springs on Thelve, Sklorn, Raerest, and Askalet, and rock-basin pools where abundant fresh water (mainly from winter snows and summer fogs) collects on all of the islands. Only Thelve and Raerest, the two largest islands, are large enough to have true (as opposed to 'saltwash') swamps. The origins of the names borne by these islands is largely lost to lore, but are thought to all be the given or family names of various mariners or persons who settled on them in the past. The nearness of these islands to the mainland, and the fact that all of them rise steeply out of the sea with no known shoals to endanger ships, have made them much visited down the centuries.
To be more specific, the "large offshore island" I'm referring to is called Thelve. In shape, Thelve is "rectangular with five little bumps or abbreviated capes, and a large rounded 'bullnose' headland to the north." The longest straightline distance one can travel on Thelve is fourteen miles, northeast to southwest, and in general Thelve is about ten miles 'tall' (north-south) and about eight miles across (east-west). Its northern headland is about ten miles offshore from Candlekeep, but at its southern end, it lies only about five miles away from the mainland (due to the rocky promontory that thrusts westwards out into the Sea of Swords south of Candlekeep).
West to east, the three small islands south of Thelve are Arthoum, Nairn's Tomb, and Askalet, respectively. Arthoum's easternmost cape lies almost four miles due south of the southwestern tip of Thelve. Nairn's Tomb is about a mile due east of Arthoum, and its northern shore is about two miles south of Thelve's southern shore. Four miles due east of the southern end of Nairn's Tomb is the western shore of Askalet, which lies about four-and-a-half miles southeast of Thelve and about two-and-a-half miles away from the mainland at the narrowest part of Racewind Passage (the strait between the islands and the shore; the only other named water area around the islands is Skoond's Run, the passage between Thelve and the trio of Arthoum, Nairn's Tomb, and Askalet).
The arc of islands running northwest from Thelve are (east to west this time): Sklorn, Unglur, and Raerest. Some sailors call them 'the Reach' or 'Crab Reach' (crab are abundant in the waters around them).
Sklorn is roughly triangular, with its easternmost cape ten miles west of the northwestern tip of Thelve. Two miles of open water separate its northwestern cape from the southeastern end of Unglur, and the shortest distance between Unglur's northwesternmost point and the southeastern promontory of Raerest is four-and-a-half miles. Raerest's northeasternmost point is about eighteen miles from the largely-uninhabited-by-humans cliffs of the mainland that lie southwest of Cloak Wood - - though it should be noted that there are the sparsely-inhabited ruins of a number of small fishing villages south of Cloak Wood, in what the elves call Raetheless ("RAYTH-lesss") and most humans call "Cloak Bay," nestled between the Wood and the pointing-at-Candlekeep cape called "Cape Raeth").
These villages have been largely abandoned because of monster raids out of the Cloak Wood and the murderous visits of pirates and smugglers over the years, though some hardy folk still cling to the most defensible huts among the ruins (digging for clams and going out in small boats with drag-nets for crab and the fish silverfin and the eel-like laethe), and that various costers and pirate conferacies repeatedly try to use the beaches and rotting wharves for shipping purposes.
There were six villages, each located at a good natural harbour. As one moves northwest up the cape and then southeast back along the north shore of the Bay, they were: Orthul's Notch, Calyaun ("CAL-yawn"), Eldelorr ("ELL-dell-ore"), Sumbur Rock, Borlyth ("BORE-lith"), and Ausabbason ("Aw-SAW-bass-on"). The Notch occupies the little indentation about a third of the way along the inside shore of the cape. Calyaun stands at the inside base of the cape (where the shore turns from running northwest to north-northeast). Eldelorr was located at the northwesternmost end of the Bay (where the Cloak Wood, as drawn on the map, almost touches the blue of the seawater). Large and mainly overgrown Sumbur Rock stands on the north shore of the bay just west of the small point known as the Fang. Monster-haunted Borlyth (which had a shipyard, and the most sheltered anchorage in "Borlyth Bay") is at the nothernmost end of the small bay east of the Fang, and Ausabbason (still linked to the Coast Way by a clear wagon-trail that curls southeast and then northeast around the end of Cloak Wood, to join the Way just south of midway between the Way of the Lion and Baldur's Gate) is a small, deserted cluster of cottages just south of the nameless plateau of rock that formed the eastern side of Borlyth Bay.
All of the Raetheless settlements were clusters of simple, one-storey thick-walled stone cottages with slate roofs, bolstered with tree-planted earth berms on their windward sides, and bolstered with timbers and ship-salvage. (Although the islands of the Reach are free of shoals, the shore between Ausabbason and Candlekeep has many jagged rocks a mile or less offshore, and sandbars constantly form and re-form between them and the rocky beaches of the mainland. Known as "the Jaws," these rocks have claimed many a vessel drive ashore in the sudden, fierce onshore storms that afflict this stretch of shoreline in fall and winter.)
Arthoum is about a mile north to south and three miles long, a tortured landscape of largely-bare rock tunneled with seacaves and 'blowholes' that geyser-like plumes of water burst up out of, during onshore storms. It has the least vegetation of the seven islands, a rocky beach on its southern shore suitable for keelhauling large ships, a few tiny caves sailors have sheltered in from time to time, and not much else of note except seabirds and various lurking predatory sea creatures. It has no sheltered anchorages or proper harbours.
Nairn's Tomb is named for an adventurer entombed in an old dwarf-delve that comes to the surface at the summit of this steep-sided, rocky, heavily-forested island (which is a mile wide, east-west, at its largest point, and a trifle over two miles in length, north-south). The tomb was plundered long ago, and is said to be haunted by phantoms and worse; seabirds avoid the entire island for some reason. There's a sheltered anchorage halfway along the eastern shore of the island, but no beaches or proper harbours.
The entire heart of Nairn's Tomb is honeycombed with dwarf-high tunnels and chambers, that descend into unknown depths (many tales say tunnels connect to the mainland, or descend right into the Underdark [and Elminster confirms that both those beliefs are true, noting that if one can get past a certain guardian dragon - - see my Wyrms of the North columns - - one can travel between Nairn's Tomb and Candlekeep itself, underground]), and many of these chambers have been used by various smugglers and pirates over the years to imprison captives, store treasure and goods, and as temporary dwellings. Monsters do prowl the lower 'ways,' and from time to time wander up to the surface, seeking prey.
Askalet is roughly diamond-kite-shaped (with the 'short triangle' to the northwest, base-mated to a 'long triangle' pointing southeast), with the mainland two-and-a-half (north end of Askalet) to three-and-a-half (south end of Askalet) miles away across the Racewind Passage, an aptly-named strait through which winds blow briskly north to south during most sunlit hours (calms are common at dawn, dusk, and throughout most nights, but of course tend to be accompanied by thick [read: cold, wet, and clinging] fogs). Askalet has a snug two-vessel harbour midway along its southern shore, a tiny wooded valley around a spring-fed freshwater pond at its heart (easily reachable from the harbour), and half a dozen springs welling up to cascade down its rocky sides into the sea in various falls that freeze spectacularly in winter. The eastern side of the island is three-and-a-half miles long, its northern and western shores are both about two miles long, and a longer (curving) southern shore completes the diamond.
Aside from the valley, all of Askalet is a labyrinth of rocky, wooded ridges (home to many deer and an owlbear or two), there are fish in the lake, diligent searchers can find about a dozen small fissure-caves (used by the owlbears and in the past by more than a few smugglers and pirates), and the island holds at least three ruins: an overgrown, roofless cottage or hall nestled in a dell on the westernmost heights of the island; an overgrown stone manor house in the valley (long-abandoned and said to hide pirate treasure, guarded by traps), and a ruined castle at the southern end of its easternmost cliffs (said to be both a former pirate-baron's hold [false] and a onetime wizard's tower [true, and Elminster believes the name of the isle is a corruption of the name of this long-ago mage, Askalath]). All of these ruins have been searched and temporarily used for shelter countless times, but that doesn't necessarily mean they hold nothing in the way of treasure. Askalath's tower has a cellar carved out of solid rock that sports a well-like shaft descending down seemingly forever (well into the Underdark, and far beyond the reach of any known rope). If Askalath ever drew water up out of the shaft, he used magic rather than buckets on ropes - - and [true] tales say there are short cellar complexes opening off the inside walls of the shaft, "well down" its descent.
Thelve is home to no less than three castles: one on its eastern shore, atop the cliff facing Candlekeep, one at the western end of its southern shore, frowning straight across the waters at Nairn's Tomb, and one atop a rocky inland pinnacle, about two miles due southeast of the northwesternmost point of the island. All three of these castles are large, soaringly tall, impressive stone strongholds, built atop stony heights and possessing extensive stone cellars (those belonging to the eastern one extend into tunnels running several miles, to come out on the surface of the island in a valley at its center). All of these castles are home to liches and a variety of prowling monsters commanded or coerced by the liches. These liches (in life one human male, two human females) were the wizards who in life had the castles built for them. When alive, these wizards were once friends, and although relations between them became strained over the years (particularly as they prepared for lichdom), they never actively fought each other or sought to dominate the island they shared. (Elminster says the three are thought by many mages to now be under the sway of Larloch.) Their names are forgotten - - or rather, tales now offer so many wildly different names for the three that the true and proper names have been lost among the spurious inventions. "Thelve" is thought to be the remnant of a gnome or dwarven name, from before the coming of the three mages.
The island was once home to a tribe of gnomes, who were enslaved and finally exterminated by the three powerful human wizards through cruel overwork, as they were forced to build and endlessly expand the castles.
Though there's no evidence that a collective term for these three liches existed when they were alive, bards have since dubbed them "the Twilight Three." They are mighty in arcane spell rosters and collected magic items, and are said to be more cunning than insane, largely keeping hidden from intruders and letting their traps, spells (at least one of them is said to be a master of wards and barrier magics), and guardian monsters slay visitors. On the rare occasions when they are seen, they've reportedly worn crowns, filigreed 'show armor' and other finery, and to have swept along their passages in disdainful silence.
Their magics have proven too puissant for anyone to yet destroy them - - and their presence is obviously the reason the nameless ruins of three large gnome villages, in the interior of the island, remain abandoned and overgrown. Many sailors' tales warn that the liches "send forth" prowling undead and other beasts to attack anyone who tries to stay the night on Thelve.
Thelve has good three good harbours, and six sheltered anchorages along its southern shore. The harbours are Mresker's Hide, in the half-moon bay in the southern half of the eastern shore of the island, and nameless harbours at the southern end of Thelve's western shore and in the inlet due west of Candlekeep, just north of "the Gaunt" (the local nickname for the lich-castle that faces Candlekeep). Onshore winds and swift currents make anchoring anywhere along the northern shore of Thelve hazardous - - and the western end of the north shore is where a large freshwater swamp, Taglan's Bones (named for a pirate captain slain by his crew somewhere nigh its quicksand heart, after an argument over hiding treasure there) empties into the briny 'Cauldron of the Reach' (a cartographer's term used by sages, scribes of Candlekeep, and bards, never by sailors familiar with the area).
Sklorn is a misshapen equilateral triangle, with its west and south sides vertical and horizontal (and its roughly-nine-mile-long northeastern shore diagonal). Its south shore is approximately eight miles long, and sports two good anchorages flanking a central harbour (called "Sklorn's Rest" by some sailors, though some writings kept at Candlekeep suggest that Sklorn wasn't a sailor but rather a clan of humans or even half-orcs who once dwelt on the island). The other good harbour on Sklorn is at about the midpoint of its western shore; both harbours are washed clean by freshwater streams flowing down from the island's rocky interior.
Much as The Hooded One posted to you earlier, Sklorn is one of the two islands aptly described as follows: much used by pirates, and so littered with the wrecks of beached, scuttled, and half-burned ships. Sklorn is usually inhabited by a few monsters and castaways - - and is always home to uncounted thousands of squawking seabirds (mainly "gray coasters," large (and gray-fledged but with white underbellies) seabirds that can have eight-foot wingspans, and are something between a pelican, a cormorant, and an albatross: unpleasantly oily, but fat, stupid, and edible). Small colonies of seals lair along its the southern shore.
Unglur is the other pirate-littered island of the Reach. Like Sklorn, it has no visible ruins, and only a few seacaves for shelter. Unlike Sklorn, it has no freshwater springs (and very few seals, monsters, or castaways), and (thanks to the gray coasters and rock gulls), its trees and shrubs are visibly thinner. Otherwise, it, too, sports many wrecks of beached, scuttled, and half-burned ships. It is also said to be haunted by the long-clawed spirit of Unglur [note: if you have the MONSTER MANUAL III, use a boneclaw in place of the unique undead I crafted rather carelessly back in 1983] a bloodthirsty berserker among pirates in his day.
Unglur is the shape of a capital letter "P" with no hole in the middle, its upright 'back' running five miles northwest-southeast, its bottom stem being a mile across and running back northwest up its eastern side for about a mile before bulging out two miles north to begin the 'curve' of the 'P.' Unglur has no harbours, but does have an anchorage midway along its western shore, and a place where boats of all sizes can readily be beached where the stem and the bulge of the 'P' meet, on its eastern shore (prevalent winds make beaching easy, but getting a boat off again a matter of magic or much muscle on the part of parties of strong men on lines, or rowers on vessels offshore).
Raerest is the largest and outermost of the seven islands, being about the size of Thelve but with the addition of a three-mile-long-and-wide 'tail' jutting southeast off it (the longest straightline distance one can travel on Raerest is just under seventeen miles, north to south, and in general Raerest is about ten miles across, from east to west).
To some extent Raerest shelters the other six islands from the prevailing local winds, and is called 'the Prow' by some Sword Coast sailors for this reason. The eastern shore of this island offers almost a dozen good anchorages, but the winds and currents rake its other shores.
Raerest is dominated by 'the Shield,' a huge spine of high rock that curves along its westernmost edge. From end to end of Raerest several different sorts of rock can be seen, not just the uniform granite of the other islands, and the upthrust rocks of the Shield hold much soft, easily-gleaned copper; in many places a man with a sharp tool can carry off a basketful of very pure ore in a day, and many small embrasures and hollowed-out holes scarcely larger than the insides of coffins betray the minings of the past.
At the heart of Raerest are a line of three tiny, spring-fed lakes (paralleling the eastern flank of the Shield. At the northern end of this chain of lakes is a large, nameless freshwater swamp inhabited by lizardfolk, who regard Raerest as their own and hunt across it, hurling nets to take seabirds, setting out tidal weir-nets to reap fish from the sea, and maintaining clam beds in the swamp-mouth sands. They will hide from intruders until what they see as the right moment to attack.
At the southern end of the chain of lakes, in a bay on Raerest's southeastern shore, is a splendid natural harbour. Its shores are covered with in the overgrown ruins of Roaringcrest, a onetime pirate stronghold that was destroyed in an afternoon by one of the Twilight Three, unleashing deadly spells that left the port a place of wild and unreliable magic, where a crimson death and a darktentacles are known to lurk, and deadly automatons stalk. Sword Coast pirates tell lurid tales of the treasure that lies scattered for the taking in the collapsed and riven homes and sheds of Roaringcrest-treasure still largely unclaimed, in the face of its waiting perils.
And that's all I have on these seven islands. Not much, but certainly enough to get in the way of some campaign plans. Jerry, if it's the tabula rasa sort of terra incognito you need for your campaign, most of the Pirate Isles off the Sword Coast are entirely undetailed, and NDAs still cover the offshore islets near Baldur's Gate.
These particular so-close-offshore islands received this level of detail because I intended them as a campaign setting if the mages in the Company of Crazed Venturers relocated to Candlekeep (one of my players had expressed an interest in "conquering Candlekeep from within and becoming its defenders," so as to have what he saw as the PERFECT base for an adventuring company: access to all the spells he could think of, and a huge staff of servants/defenders. The idea never got off the ground, thankfully, though I did use the Raetheless for one of my limited-duration "library campaigns" in 1989.