Artifacts are the notes, letters, maps, diagrams and personal items you pick up across The Last of Us Part I and Left Behind. Collecting every one, together with the notes, earns the Chronicles trophy.
Picking up an artifact adds it to your collection. Combination notes double as safe keys: once you hold the right note, the matching safe can be opened.
Chronicles asks for every note and artifact in the game. A separate trophy, In Memoriam, is tied to one note in Bill's Town that you have to pick up again after it gets thrown away.
Abandon Zone Note
The Abandon Zone Note sits on the desk in the office at the far left end of the bookstore's first floor in Pittsburgh.
Ambush Map
The Ambush Map is pinned to the wall of the room at the end of the hallway. Leave the stairs in the room with the two dead bodies, follow the corridor to its end and look on the wall.
Applicant Checklist
The Applicant Checklist is under the stairs on the far left of the bookstore's ground floor in Pittsburgh.
Atrium note
The Atrium note is an artifact in the Left Behind DLC chapter So Close, set in the present-day Colorado mall. It is in the atrium, to the left of where Joel and Callus are hidden, near the remains of a field surgery.