Logbooks are the collectibles that push you deeper into The Mound: Omen of Cthulhu. There are 13 of them, and each one you carry back to the galleon opens a new starting location for future expeditions. Pull all of them and you unlock the full set of 18 maps, which brings more contracts and areas into play. Two achievements are tied to the count, one for reaching seven logbooks and one for all 13.
Quick answer: Pick an area on the map that is joined to others by dotted white lines, travel to its fort, grab the logbook from the small white tent inside, place it in the ox cart, and extract safely by returning to the boat. The unlock only counts once you leave the area alive.
What logbooks unlock in The Mound
A logbook is a record left behind by an earlier expedition. Recovering one gives the captain the knowledge to approach a new region, so it becomes a fresh starting point you can select from the map. That is how the game gradually opens deeper areas as you close the distance to The Mound.
| Detail | Value |
|---|---|
| Total logbooks | 13 |
| Maps unlocked in full | 18 |
| Achievement milestones | 7 logbooks and all 13 |
| What each one grants | A new starting location and additional contracts |
Spot the areas that hold a logbook
After you sign a contract and reach the location screen, look at how the areas connect. Any map joined to others by dotted white lines contains a logbook. Those are the destinations worth targeting when your goal is to unlock the next region rather than to chase treasure.
You do not need a special mission to collect one. A logbook can arrive as its own objective, or you can simply pick it up while running a different expedition in the same area. Starting with a basic contract keeps the run manageable while you learn the layout, and you can skip the harder contracts that specifically demand a logbook.
Find the fort inside the area
Every logbook sits inside an abandoned fort, and the fort is the hard part. Its location is not marked, so you have to read the terrain as you move. Forts usually sit at the end of the road heading north.
Grab the logbook and get it out
Inside the fort, the logbook waits in a small white tent marked with a flag. Interacting with it uses the on-screen prompt for the fort logbook, and the objective text reminds you that retrieving it maps a new area.
Note: The logbook only counts if you return to the boat and get out safely. If the run wipes before extraction, the unlock does not register.
Use an Area Map to stop getting lost
Navigation is the biggest obstacle, since the areas loop back on themselves and dead-end often. Before heading out, buy an Area Map from the shop for 30 coins. It gives you an outline of the region and shows your own position as you move, which makes the trek to the fort far less confusing.
Keep one limit in mind. The Area Map shows the layout and where you are, but it does not pin the fort’s exact spot. You still have to spot the tower and walls yourself.
How to confirm the unlock worked
Back aboard the ship, a short cutscene confirms the crew recovered a logbook from a previous expedition, and a new recording becomes available to listen to. From there you can select the newly opened region on the map for your next run. If you did not reach the boat before dying, the region stays locked and you will need to attempt the fort again.
Once the count grows, the achievements trigger at seven logbooks and again at all 13. To reach the full 18 maps efficiently, keep chasing the dotted-line areas one at a time, hold off on unnecessary fights and treasure detours until you know the layout, and always prioritize a clean extraction over a bigger haul.
