Finding the O near Pleasant Park, S in Wailing Woods, M in Dusty Visit, N under Frozen Lake and Retail Row NOMS locations is the objective of one of Fortnite's many Weekly Challenges.
Completing it will give you additional XP to help go towards your many Season 7 rewards.
If you're just getting started, our Fortnite Battle Royale tips and tricks can provide some helpful hints.
Fortnite letter locations at a glance
For the Week 4 Challenges, you are tasked with the following, which unlock in sequence:
Here are the letter locations at a glance:
First, you don't have to worry about whether or not this needs to be completed in one match, obviously, as unlike most other challenges, you only need to do it the one time.
Second, when you have found the letter, you must get up close and press the button prompt, interacting with it and completing the objective.
Here are their locations in further detail...
Fortnite O near Pleasant Park location
West of Pleasant Park is a decrepit house standing alone in the middle of the forest. Make your way there, and underneath the house's south-east corner, you'll find the letter O location by a skip.
Pick it up, and load up another match - the S in Wailing Woods location is up next.
Fortnite S in Wailing Woods location
The letter S in Wailing Woods is location is inside the hidden research base underneath the location. First, locate the fortified maze, and land inside the central structure. Use your axe to dig down, and you'll appear underground.
Crawl underneath the shutter and turn left, looking north-west, to see some offices. Enter one of the doorways, and locate the office in the center.
Look behind the door, and you'll see the letter S location on the ground.
With that done with, the letter M in Dusty Divot location will appear from the next match you play.
Fortnite M in Dusty Divot location
You'll find the letter M location in the divot itself, specifically inside the south-east research building.
Once inside, turn right, and open the door. The letter M location is in the corner.
Now for the 'N under Frozen Lake' location.
You can unlock Fortnite Season 7 skins and emotes with each week's set of Fortnite Challenges - the latest including Chilly Gnome locations and Expedition Outpost locations. Other recent additions include Fortnite plane locations and Snowfall secret Battle Star locations.
Fortnite N under Frozen Lake location
Within the map's icy region is a frozen lake where Greasy Grove used to be. Head there, and locate the roof of a building buried in the ice in the middle of the lake.
Smash open the roof with your axe, and drop down inside. In the north-west corner is a till and some shelves. Next to those, leaning against the wall, is the letter N location.
Final step now to come - the Retail Row NOMS location.
Fortnite Retail Row NOMS location
The fifth and final location has you go to Retail Row to find the NOMS location - NOMS, if you haven't noticed, being the combination of all the letters you've found so far.
You specifically need to go to the north-east of the location, at the large store on the north side.
Land in the car park, and approach the front of the store, where you will see the sign up above on the wall. The challenge should unlock automatically - no button prompt needed.
And with that, the long letter search is over!
Already done? There are plenty of other Challenges to take on this week - so keep playing!