When you reach a certain point in the game, you'll obtain a "special radio" with a longer dial that allows you to find
"radio beacons" hidden around the island. Every one of these secret stashes contains one of the 13 Maggie's Letters. The exact point where this starts is
and it has a point of no return, that is when you
In order to find the letters, you'll have to
tune your radio to 140.1, and a voice will give a little clue about where the letter is located.
They aren't hard to find, and
a little shining light marks the letter location as you get near, but as these audio clues aren't subtitled and they are given using the NATO alphabet (you know, Charlie, Alpha, Tango, Zulu, etc), it could be troublesome for non native english speakers.
So here's a list of all the 13 letters.
You must find them all in the same playthrough. The first one is automatically obtained as part of the story, and
every location has one except for Adler Estate, and Main Street has two, counting the automatic one. You can get them in the order you want after you got the first one, but I'll also add the letter number as they appear in the menu, in case somebody is missing a certain one (thanks
tobiasvl).
1 - Main Street (Letter #13) - Obtained automatically along with the "special radio" inside the Parks And Facilities Office, as a part of the main story.
2 - Main Street (Letter #4) - In front of the Guest Information Centre, located in the parking lot that is near the boat pier.
IMPORTANT: As
hxc Frankie said, for some people, letter #4 is located in front of the Antiques Shop, which is the small building left of the Parks And Facilities Office. As the audio clue talks about antiques, I guess this should be the real location.
3 - Discovery Cliffs (Letter #6) - Near the brown coloured zone in the top part.
4 - Beacon Beach (Letter #12) - At the bottom of the stairs, near the fence that blocks the cave entrance.
5 - Epiphany Fields (Letter #1) - In front of the lighthouse, near the left border of the zone.
6 - Harden Tower (Letter #3) - In the last bend of the path that leads to the tower.
7 - Towhee Woods (Letter #11) - In front of the fallen tree, bottom right.
8 - Bridge Stand (Letter #8) - In the small graveyard, bottom left of the screen.
9 - Camp Grounds (Letter #9) - In the ruined lookout point, top left of the screen.
10 - Relay Point (Letter #10) - In front of the water well.
11 - Milner Outpost (Letter #2) - At the bottom of the ladder of the water tower.
12 - Facilities (Letter #5) - In the room with three beds, bottom left of the screen.
13 - US Army RCS (Letter #7) - In front of the direction signpost, left of the big tiger painting.
Leading to this achievement, that requires all 13 letters, you'll also get: