The City of Veil
The Dawnguard was once the most prominent ash company in Veil. They discovered the Shrouds (and that the city of Veil used to be bigger), the Iron Fields (where centaurs roam across the plains under abandoned grove cities in massive trees), the Hushwoods (A heavily forested area covered in mists that rise above an area only known as the Undergrowth), an ancient civilization only known as the Kingdom of the Five Thrones, the North and South Khardur mountains, Reohm’s Book, and the hills of Malgrimm (where there is a heavily fortified city, unknown if it’s occupied).
The Dawnguard pretty much mapped what Veil knows exists. Although there is still a lot they do not know.
As a result, the Dawnguard became popular and famous, working with the Conservatory to discover the history of Veil.
Now, they are the sworn protectors of the city of Veil with membership ranging in the hundreds. They patrol the gates, the walls, and the streets making sure all the citizens are safe.