Hello, this question has been bothering me for years.
I've been going through a bunch of maps, faerun locations and landmarks and this has entirely been annoying me. None of the terrain really fits anything between Baldurs gate and Elturel being smack bang in The Fields of The Dead noted as being miles and miles and miles of rolling hills and grassland, and On the actual river which takes any and all instances of mountainous terrain out of the equation entirely. This is my Dilemma.
Using the 2 instances of images provided by Evil there and using other images of the land. Trying to research the location of Anga Vled (which is only estimated in the research I have come across), The angles of the river in Act 1 I can only find 1 or 2 possible locations.
Firstly, let me show a fraction of the image that I use for most of my Faerun geography and large scale campaign settings that I find reasonably accurate.
[img]
https://postimg.cc/ygb24N7x[/img]
Next I Look for distinguishable features in the actual BG3 Map. The most notable is a 90 degree bend north in the river and mountainous terrain surrounding it. After Scouring the 2008 forgotten realms campaign guilde and The Sword Coast Adventurers Guide these have proved very poor. Even The Code of The Harpers, an old 2e book only heightened my worries.
My main issue is with the 2nd image where skuldask road is. If this is in fact accuate (skuldask road appears differently nearly everywhere with this image being the closest to that angle)
[img]
https://static.wikia.nocookie.net/f...ad.jpg/revision/latest?cb=20110623185348[/img]
This would indicate that Moonrise Towers are essentially right next to Elturel, placing the game's landing location east of or in Elturel
So.... one of a number of things has transpired here... The devs got it very very wrong (most likely. considering their incorporation of D&D ruleset in to their game rather than being a true D&D game) or simply changed the location positions in the world. Every source I have found places moonrise essentially directly to the west of Elturel.
There is another that the locations given are wrong, but as the Crescentcoat high office would imply it is indeed very close to Elturel, the variance in positioning isn't really an issue.
But let's look at the situation as a whole.... The Tieflings have been on the road from Elturel to Baldurs Gate due to being exiled after elturels return, Moonrise is due west of elturel and they would reasonably be following skuldask road and thundars ride to Baldurs Gate. If we look again at the map I generally use, look at the geographies of the map and the game I have come to settle on that the game is using this area marked and changing the positions of landmarks and pois to suit. None of it should be considered canon.
[img]
https://postimg.cc/Fd6W7ndH[/img]
the area to the left is the one I'm convinced they're using due to the river angle and a the most likely (exaggerated from hill to) mountain terrain, corroborated by western heartlands map. possibly the smaller one as it's closer to the road with moonrise, in this game, being west of the hills next to my mark.
So that's my idea on "where" this game takes place.