Stranger Things 3: The Game

In Hawkins Suburbs, there is a house with a pool in the backyard. Inside this house is someone who wants you to find 50 garden gnomes scattered around Hawkins – and in his house, you can open a chest for every 10 gnomes you find. Keep this in mind, because the chests contain some good crafting supplies/trinkets.

By the time you start Chapter 8 (final chapter), you can have 49/50 of the gnomes – all except #5.

Tenreth over on TrueAchievements.com has compiled a list of the gnomes and their locations, which I'm replicating here with some extra comments as necessary.

Number - Name - Location - Description

Gnome #1: Johnny - Hawkins Suburbs - In Mikes Basement (it's the one you start every chapter) right behind the D&D desk near the exit towards the stairs.
Gnome #2: Christine - Hawkins Suburbs - Leave Mikes house by the front door. It's at the flowerpot directly south.
Gnome #3: Doc - Hawkings Mall - Outside near the loading area on the west side of the map.
Gnome #4: Indiana - Hawkins Suburbs - In Hawkings pool on the outside area near the shack at the right side of the screen.
Gnome #5: Chunk- Weathertop - During the last chapter, when you're looking for Cerebro, you find yourself in some underground dungeons. In the 2nd one, there is a small exit at the right side of the map near 3 huge tanks. Leave the dungeon and the gnome is right there. (Secret Badge needed – get the badge from Murray at Starcourt Mall. Enter the shack, use the badge, go through the first bunker/secret tunnel and enter the second one. In this new secret tunnel/bunker, you want to make your way E/NE – there's a really long hallway that ends with a room with a bolt-cutter gate (Medkit behind it) and a room with three orange tanks. In that tank room is an exit that leads back outside to a small closed-off area with this gnome in it).
Gnome #6: Elvis - Hawkins Square - Behind the trees in front of the public library (huge building with blue roof).
Gnome #7: Jack - Hawkins Square - In the library in the "last" room of the first area near the computer.
Gnome #8: Flynn - Starcourt Mall - Parking lot near the green car at the bottom.
Gnome #9: David - Weathertop - Northern part of the map, underground entrance, follow to the end of Secret Tunnel
Gnome #10: Baskin - Starcourt Mall - Behind the counter of "Scoops Ahoy!" on the lower level.
Gnome #11: Macdonald - Driscoll Farm - East corner of the map.
Gnome #12: Clint - Hawkins Square - In the Hardware Store, you need Joyce to unlock the chaind door. The gnome is behind some cardboard boxes.
Gnome #13: Marty - Hawkins Square - In the Hardware Store, East corner of the first room.
Gnome #14: Mikhail - Hawkins Square - In front of the town hall hidden behind the the lamp post between two bushes.
Gnome #15: Denver - Driscoll Farm - While doing the quests there, you'll have access to the barn. While inside the barn, leave by the other exit to the left and use the secret passage behind the barn.
Gnome #16: Drago - Hess Farm - Once you're in the Lab, you can craft cranks to enter some optional rooms with loot. You can buy the material needed at the vending machine in the area. You need 3 cranks for all doors. The gnome is in top left room.
Gnome #17: Fletch - Hawkins Suburbs - In the Abandoned House, crawl into the vent and use the computer. Enter those numbers: 5-7-2-5-7 > 7-3-7-9-7 > 7-7-9-2-7 > 8-7-7-4-2 > 1-4-8-4-7 . This unlocks the room with the gnome and some chests.
Gnome #18: Norman - Hawkins Suburbs - Granny's house (when you get the side quest for cleaning her back yard).
Gnome #19: Herbert - Hawkins Suburbs - Granny's house inside the basement behind some rocks (you need bombs).
Gnome #20: Burt - Hawkins Suburbs - Inside the pool area behind the chained door (Joyce).
Gnome #21: Seth - Hawkins Square - In the back of the flower shop. Let the golden bear statue face the flower pots, then crawl through the vents and let the rat face the sink. The gnome is behind the door, that opens.
Gnome #22: Rutger - Hawkins Suburbs - Inside the pool area when you check the girls locker room during a main mission. It's nearly impossible to miss.
Gnome #23: Cruise - Hawkins Square - In Circuit Shed, open the chained door and make your way through the light puzzle in the last room. The lever in the room in front of the puzzle room does not turn the lights off.
Gnome #24: Charles - Hawkins Lab - Behind the vent accessible with Erica. You have to solve a simple lever puzzle.
Gnome #25: Kitt - Hawkins Lab - At the entrance, go up from your spawn location. It's behind the trees (go left from the entrance and follow the path until it stops).
Gnome #26: Huey - Hawkins Lab - During the timed event, when you have to activate both pressure plates the gnome is near the desk in the same room.
Gnome #27: Falco - Hawkins Suburbs - In the bush behind the fence, north of Dustin's house. It's the house with the workbench on the outside. You can get behind the fence at the lower end.
Gnome #28: Glenn - Hawkins Square - Inside Hardware store crawl through the vent with Erica. The area is very small and two enemies await you. Be prepared!
Gnome #29: Sonja - Hawkins Suburbs - In Max's backyard when you pass through this area during a main mission. It's near the two green containers.
Gnome #30: Ripley - Hawkins Square - Inside the City Hall in Aide's office.
Gnome #31: Tony - Hawkins Square - Inside City Hall in the Gym, hack the terminal in the corridor after leaving the second elevator.
Gnome #32: Charlene - Hawkins Square - Inside the City Hall cellar behind the door that needs to be hacked. Clear the rocks with bombs and fight the rats. It's at the end of the corridor.
Gnome #33: Willie - Hawkins Square - Inside City Hall in the bathroom behind sink. The bathroom is behind the brown door near the computer you'll use to get some clues for the lever puzzle.
Gnome #34: Arnold - Murray's Warehouse - On the outside, pass between the house and the car and follow the fence.
Gnome #35: Falken - Murray's Warehouse - This one is in the 2nd room, the one with all the pressure plates, levers and statues. You have to activate switch #1, 2, 3, 5 and 8 (Start on the far left).
Gnome #36: Bastion - Starcourt Mall - Lower floor, directly at the escalator in the corner. You can see just the red hat.
Gnome #37: Magnum - Hawkins Square - Hawkins Post building, East corner
Gnome #38: Clara - Hawkins Suburbs - In Mikes House, in front of the fridge at the first floor.
Gnome #39: Deckard - Hospital, second floor, requires Erica
Gnome #40: Tommy Lee - Starcourt Mall - In the docking bay lair when you stand on a pressure plate to open a door you'll pass a vent right before some tanks and more vents. Crawl into the first single vent.
Gnome #41: Adora - Hess Farm - Shed, middle of the room.
Gnome #42: Samantha - Hess Farm - In the basement behind the vent on the left side of the map.
Gnome #43: Alexandre - Hawkins Suburbs - Dustin's House behind the pressure plate door, crawl into the vent.
Gnome #44: Papa Gnome - Hawkins Suburbs - In the pool inside the Women's Locker room through the vent.
Gnome #45: Gunther - Hawkins Fair - In the woods behind the funhouse.
Gnome #46: Tubbs - Hawkins Suburbs - In Max's House (black roof, left side of the map) behind the vent accessible from the bathroom.
Gnome #47: Coleman - Hawkins Fair - Pay 10 tickets and see "world's smallest person" (it's a gnome ) You can get tickets for different actions once or farm the whack a mole game with Eleven. She is ranged and does good AOE damage. I got 5 tickets every time. (1 ticket from the guy at the entrance, 5 from the guy who wants you to find his car keys (they're in the SE corner of fair), play Whack-a-Mole ($5 – 1 ticket per dummy hit), 2 in a chest in the NE of the woods, 1 in the booth with the dumbbell in it, 3 for guessing the girl's weight while in the booth (it's obvious), Shooting Gallery ($5, not worth it for the payout). Give 10 tickets to the fair worker standing in front of the woods area next to the toilets and pick up the gnome behind him)
Gnome #48: Slash - Hawkins Fair - In the Funhouse, 1st floor use those exits: Bottom Right > Top Right > BR > TR > BR (in the room leading to the NE-most one, you can use the right exit. It will take you to the room with the gnome and won't teleport you back to the beginning like all the other paths do.)
Gnome #49: Freddy - Hawkins Fair - In the Funhouse 5th floor when you need the answers for the clown faces. It's the right exit in green room with 3 exits (In the green room with the three juggling clowns, take the right exit).
Gnome #50: Jareth - Weathertop - In the shed to the right, crawl into the vent with Erica and use the exit on the right side in the next room.