The strongboxes do not appear in the game world until the orders that describe their locations are obtained and read. They can be opened with the Dawnguard Cache key, or they can be picked like any other locked container. They are usually placed in areas that keep them relatively hidden, making them difficult to find, even with knowledge of their location.
The locations to Dawnguard Caches can be found on orders given to Dawnguard field agents. The orders request that the agent restock several listed supply caches in the area that the novice is found in. The agents also carry keys to the caches. They cannot be engaged in conversation or aided in their orders, so they need to be either pickpocketed or killed to get their orders and key.
- In Rorikstead, in the pasture behind Frostfruit Inn, between a fallen tree and the fence.
- Near the Shrine of Stendarr in the unmarked location of The Two Pillars. This location is in the center of the tundra in Whiterun Hold, South of Swindler's Den. The cache is southeast of the Shrine.
- South of Whiterun's Western Watchtower. The cache in on the island in the middle of the stream near its source.
- On the small island nearest the Solitude Sawmill wheel, in a hollow tree trunk.
- At the eastern end of the Karthwasten bridge, south of the road, under an old tree with Hanging Moss. (It's faster to travel West on the road from Broken Tower Redoubt).
- Due east of the entrance to the ruin Volskygge, under the big limb of the large fallen tree.
- In Morthal, on the islet due east of the mill, next to a tree.
- Outside Nightgate Inn, at the foot of the pier
- Near Winterhold, under the great arch, just north of the Shrine of Azura