Where is the Dam Testing Annex Key door?

Inside the Testing Annex compound on Dam Battlegrounds, south east of Small Creek. Both doors sit on the ground level off the same back hallway, one toward the south side and one toward the east, reachable from the parking lot entrance.

Why are there two Testing Annex key markers on the map?

Because the key fits two separate locked doors in the same building. Our map marks both. One key opens only one door, so you need two keys to clear both rooms in a single raid.

Which Testing Annex door should you open first?

With one key, most guides favour the first room for better overall odds. The second room has the higher ceiling thanks to a possible field depot crate spawn, so it is the pick when you are hunting a big single item.

How do you get the Dam Testing Annex Key?

It is a rare random drop that can appear almost anywhere, with better odds in residential POIs and facility interiors. The quest A Lay of the Land awards one as the only non random source.

Do raid conditions change the Testing Annex loot?

Guides consistently recommend running it during a Night Raid for better rolls, with Electromagnetic Storm and Cold Snap also reported to raise the value of what the rooms contain.

Dam Testing Annex Key Location in Arc Raiders

Dam Testing Annex Key location in Arc Raiders: both locked doors inside the Testing Annex on Dam Battlegrounds, which room to open first, and the loot inside.

Category: Key & Keycard Locations · Updated 2026-08-02

Dam Battlegrounds map in Arc Raiders with the Dam Testing Annex Key locked doors marked at Testing Annex, south-east of Small Creek — Dam Battlegrounds. The 2 reticles mark the locked doors the Dam Testing Annex Key opens, at Testing Annex, south-east of Small Creek. The key itself is a random container drop.

Short answer

Where to find it and where to use it

The key is a random container drop and it can land almost anywhere on the map. Search priority still matters:

Residential POIs: Ruby Residence, Pale Apartments and Ben Welder's Sunroof. Drawers and cabinets over loose shelving.
Facility interiors: Research and Administration, Primary Facility and the Testing Annex itself. Desks and filing cabinets.
Off other raiders: A rare key is worth checking every body for.
The quest A Lay of the Land: Completing it awards one, which is the only non random source.

Being rare rather than epic, these turn up often enough to run regularly, but not so often that you will casually hold two. That matters more here than on any other Dam key.

What it unlocks

The item text reads "Unlocks a door in the Testing Annex on Dam Battlegrounds." The important detail the text leaves out is that there are two qualifying doors, not one.

Both sit on the ground level of the Testing Annex, off the same back hallway, with one door toward the south side of the structure and the other toward the east. Guides describe that stretch differently, some calling it the back hallway on the first floor and at least one calling it a lower level, so do not fixate on the floor label. Follow the back hallway and you will pass both doors.

Two approaches into the building:

The parking lot entrance, facing back toward the Control Tower. This is the fastest way to the hallway.
The west side, under the partially destroyed sign reading "milae analyz". Same hallway, different angle.

The key is consumed on whichever door you open first. There is no way to open one, loot it, and carry on to the second on a single key.

What is inside

The two rooms are not identical, so pick deliberately rather than opening whichever door you reach first.

Room	Contents
First room	Several valuables lockers, breachable computer consoles, technological and mechanical loot spawns, a few drawers
Second room	Mechanical, medical and weapon loose loot on the consoles, several high value blue drawers, searchable computer towers, a possible field depot crate spawn

Documented pulls include blueprints, sensors, magnets, heavy gun parts and legendary weapons such as the Snap Hook and the Anvil Splitter. Most guides give the first room the better odds if you only have one key, while the second room has the higher ceiling because of the crate spawn.

Raid modifiers matter here more than at other doors. Night Raid in particular is the run people recommend, with Electromagnetic Storm and Cold Snap also reported to raise what the rooms roll.

Is it worth the detour

Yes, and it is the most flexible key run at the Dam because it is repeatable in two directions.

Bring two keys when you can: Both rooms in one trip is the whole play, and the second key roughly doubles the trip's value for no extra travel.
Alternate doors across runs: With one key, open the door you did not open last time. The rooms reset every raid.
Barricade behind you: A Door Blocker gadget on the room door means the loot cycle finishes without an interruption.
It is off the center fight: The Testing Annex sits on the eastern side, well away from the Primary Facility and Control Tower crush. Swampside Elevator is the natural extraction from here.

Compared to the Control Tower room, the ceiling is lower but so is the risk, and you are not trapped at the top of a tower with one exit. On a 30 minute Dam raid there is time to hit the Annex and still work a second POI on the way to extraction.

How keys work in Arc Raiders

Key mechanics are identical across every map, and they matter more here than anywhere else because of the two door problem.

Single use: The key is consumed on the door. This is exactly why one Testing Annex Key cannot clear both rooms.
Lost on death: Safe Pocket or nothing. A rare key in your main bag is a gift to whoever kills you.
Rooms reset between raids: Both rooms refill, so you can alternate doors across runs instead of hunting two keys at once.
Keys drop from containers and from players: Cabinets, drawers, desks and lockers roll for them, and other raiders carry them until they extract.

Every Dam key weighs 0.25 and sells for 100 coins, which is nothing next to what is behind the door.

Other keys on Dam Battlegrounds

[Dam Control Tower Key](/guides/dam-control-tower-key-location): epic key, the control room at the top of the Control Tower, the richest and most contested room on the map.
[Dam Staff Room Key](/guides/dam-staff-room-key-location): uncommon key, a ground floor room in Research and Administration, the best reward per rarity door at the Dam.
[Dam Surveillance Key](/guides/dam-surveillance-key-location): uncommon key, a first floor room in Water Treatment Control, the lowest risk key run on the map.
[All Arc Raiders key locations](/guides/arc-raiders-key-locations): every key on every map in one place.
[Dam Battlegrounds map](/maps/dam-battlegrounds): full interactive map with POIs, extractions and every key marker.

Frequently asked questions

Where is the Dam Testing Annex Key door?: Inside the Testing Annex compound on Dam Battlegrounds, south east of Small Creek. Both doors sit on the ground level off the same back hallway, one toward the south side and one toward the east, reachable from the parking lot entrance.
Why are there two Testing Annex key markers on the map?: Because the key fits two separate locked doors in the same building. Our map marks both. One key opens only one door, so you need two keys to clear both rooms in a single raid.
Which Testing Annex door should you open first?: With one key, most guides favour the first room for better overall odds. The second room has the higher ceiling thanks to a possible field depot crate spawn, so it is the pick when you are hunting a big single item.
How do you get the Dam Testing Annex Key?: It is a rare random drop that can appear almost anywhere, with better odds in residential POIs and facility interiors. The quest A Lay of the Land awards one as the only non random source.
Do raid conditions change the Testing Annex loot?: Guides consistently recommend running it during a Night Raid for better rolls, with Electromagnetic Storm and Cold Snap also reported to raise the value of what the rooms contain.