Thoughts on Western Brun
by LoZompatoreJust to add a few canon information to what Zendrolion already said. Most of them were already published somewhwere (maybe here on the Piazza) in a topic about Karawenn I'm not able to find anymore.
Anyway, what follows here is what I wrote at that time. Some info are already widely known, others were already listed by Zendrolion and the others; I'll publish the whole block mostly because I'm lazy
1) The smallest lake should be the spring of the Yalu river. If so, from Dungeon Magazine #6-7 ("Tortle of the purple sage" adventure) we know that it is called "Spring of Good Health" and that it may have some connection with the Frosthaven Sea. In the other parts of the module it is said that there is not a direct waterway between the spring and the Frosthaven sea, but there should be some kind of path or connection anyway, because at the end of the module it is suggested a quest in order to reach the Frosthaven Sea starting from the Yalu's spring.
Page 41 of DMG#6:
The legend states that the Great Northway (aka the Yalu River) is a broad and mighty river which flows southward for thousands of miles through desolate grasslands. At its source, the legend says, lies the Spring of Good Health from which the waters of the great river run rich with earth.
Some say the Great Northway is not a river but a channel to the arctic waters of Frosthaven (this rumor is false). If so, ships using the channel could easily reach all parts of the Known World. Along the river's shores, the legend relates, live fierce, undeducated savages who pray for floods.
During the floods, islands covered with animals float down the river and into the sea.
Suggestion: If you want to place the Karawenn area in this region, maybe it would be nice to magically connect the great canyon of the Karwenn with the maelstrom in the northern shore of Norwold. The two areas might well be two connected gates to the Elemental Plane of Water. A lucky explorer may find himself in the lake or in the Frosthaven Sea if he manages to survive to the terrible experience of being sucked inside one of the gates.
2) About the neighbouring areas we know from GAZ10 that the biggest lake is called "The Cradle", and that it was an important stop of the great Wogar's migration from Urzud. Before Wogar, the same route should be used by the humanoid chief Ungar, who first stole the Blue Knife from Urzud and escaped with his followers (GAZ10, again).
From GAZ10, the city of Urzud should lay just east of this lake, at the crossing of the two main branches of the north-flowing Borea river.
3) From the "Prelude" article of the "World in Flames" campaign written by Heard we know that not far from Urzud live at least two humanoids tribes: the Othwa (goblins, followers of Wogar) and the neighbouring Gronmak (orcs, a very large tribe, they are not followes of Wogar), plus some other unnamed lesser goblin tribes. Even if you don't use the Heard's campaign assumptions, I think it's a good idea to include these tribes in the local geography of the area anyway.
4) From the Dragonlord Trilogy (Book 1) we know that the whole area is sparsely inhabitated by svage humans and elves, and by a lot of dangerous monsters (unluckily we don't know which monsters they are). The dragons themsleves do not care very much about this region and they tend to avoid it. Notice the Dragonlord Trilogy is set around AC500 so things could be different by now. Here is the relevant excerpt:
Their first day of travel brought them back down from the mountains of the Hyborean Reach to the very edge of the seemingly endless wilderness that lay beyond...The next day led them into the wilderness itself, a great sea of forests and plains extending for hundreds of miles across the northlands. None of them knew quite what to expect. They had all heard vague rumors that this was a land of primitive folk, men and elves who lived mostly by hunting, but also of many strange, deadly monsters that haunted the dark woods. No one from the civilized lands ever came here, for there was simply no reason. There were no cities or towns, no trade nor any other lure. Even Kharendaen [a gold dragon] could tell them little of this land. The dragons seldom came here, and when they did, they remained aloft on their west to the Hyborean Reaches or the Endline Mountains farther south. What Kharendaen did know was that this land wasn't safe for travelers, and trouble was certain to follow if they didn't take some very careful precautions...
The very presence of a gold dragon was quite enough to convince most other creatures to keep their distance, and they weren't threatened during the entire trip. But the woods were still dark and hostile, and they all sensed that danger always lurked nearby...
They were coming into the deep northern forests of western Wendar now, forests that were said to be inhabited by tribes of wild elves. The trees were taller and denser than in the wilderness beyond.
5) From CM7 ("The Tree of Life") we know that there are some human civilized cultures sourrounding the Sylvan Realm, just east of the mountains (the Sylvan Realm is visible in my map: it is along the western coast of Brun, where I put a couple of small rivers and lakes; this is the position stated in CM7 and in GAZ5). From these realms possibly came the evil mage Moorkroft.
Remember that, from the Dragonlord Trilogy, in this area the mountians are called "Hyborean Reaches" and that just north of the Sylvan Realm lays the Dragonwatch Keep, an highly-magical abandoned castle of Blakmoorish origin that survived the Great Rain of Fire. The castle now is used by the gold dragons as a temple of the Great One.
6) In the pre-cataclysmic era the Borea Valley was invaded by Blackmoorian crusaders who drove away (in the nowadays upper part of Norwold) the beastmens who lived in the area. So the whole Borea plain was a Blackmoor colony for some centuries (the crusade lasted from 3500BC to 3200BC). From HW boxed set we know that southern elves went to live with the Blackmoorians. Probably they did not limit themselves to colonize the Glantri/Broken Lands (and possibly Wendar) regions.
From the HW/WotI sets we know that many human tribes of Neathar race lived at the border of the Blackmoor Empire, trading wealth and technology. Among them there was the tribe of the future Immortal Djaea. Possibly these tribes were located in the central areas of Brun.
7) From the GAZ5 map we know that the Ilsundal migration crossed the continent of Brun just south of the two lakes (The Cradle and The Spring of Good Health").
8) From GAZ12 we know that the ancient Ethengarians left their original plains ("at the fringe of Blackmoor civilization") that turned into a frozen tundra and that they roamed the continent for 1000 years before settling themselves in the Ethengar Steppes. The Ethengarians should come from Brun, possibly their original home was in southern Hyborea. Their roaming should have covered the whole central areas of continent (maybe avoiding the beastmen infested areas, such as Urzud ancd the neighbouring country).