One file, in a folder named Worlds
A Terraria world is one file, which makes it easy to copy and easy to lose. The file carries the .wld extension, and the game keeps worlds in a folder named Worlds. The Terraria Wiki's own serverconfig examples point straight at that folder: world=C:\Users\Defaults\My Documents\My Games\Terraria\Worlds\world1.wld to load a world and worldpath=C:\Users\Defaults\My Documents\My Games\Terraria\Worlds\ to set where world files are stored — on your own PC that My Games\Terraria\Worlds folder, under your user name's Documents, is where the world you play lives (Server). On Linux the path is ~/.local/share/Terraria/Worlds/ and on macOS it is ~/Library/Application Support/Terraria/Worlds, which the wiki describes as "the Application Support directory in your user's library".
Nothing about the world depends on where the server program sits. World files live outside the program folder, so copying the world is a job about two folders — yours and the server's — and never about reinstalling anything. A solo world and the world you have been hosting through the in-game Host & Play option are the same thing on disk, a world your copy of the game saves, so both move to a dedicated server the same way: find the .wld, copy it, point the server at it.
Step 1: copy the world somewhere safe first
Before anything moves, copy the .wld somewhere nothing can touch it — a different drive, not the server's folders. A one-file world is easy to lose precisely because one copy is one mistake from gone, and the mistake this page is about (a server that quietly builds a fresh world at a mistyped path) is only expensive if you no longer hold the original. The wiki's own saving note ends with advice that fits any file handling: "consider saving manually prior to shutdown" (Server). Our game server backup checklist turns that habit into a routine for every world you run.
Step 2: put the .wld where the server looks
The server reads world files from the same Worlds folder convention. On Linux, the wiki's server instructions are explicit: "Place your world files in the following location for the server to find them: ~/.local/share/Terraria/Worlds/". On macOS, world saves live in ~/Library/Application Support/Terraria/Worlds. On Windows the equivalent is the Documents\My Games\Terraria\Worlds folder the config examples name. Copy the .wld into that folder on the machine running the server (Server).
The location is a setting, not a law. The worldpath key in serverconfig.txt — "Sets the folder where world files will be stored" — moves it, and a relative path there resolves against the folder holding the server program, which is how a server keeps its worlds beside its own binary. Unless you have set worldpath, the Worlds folder above is the target. The full key-by-key behaviour, including our own test of a relative worldpath, is in the Terraria serverconfig.txt reference.
Step 3: point serverconfig.txt at the world
The line that loads your world is world= with the full path to the .wld file — the wiki's own example is world=C:\Users\Defaults\My Documents\My Games\Terraria\Worlds\world1.wld. In the shipped serverconfig.txt every line arrives commented out with a leading # except priority=1, so remove the # in front of your world line and save. The file sits next to the server program — the official zip unpacks to Windows, Linux and Mac folders, each carrying its own copy — and start-server.bat starts the server using it; the file can have any name if you pass it to the server yourself with -config, and relative paths resolve against the folder containing TerrariaServer.exe (Server).
Read what that line does before trusting it. It loads the world and starts the server on it without asking any questions — and if the file does not exist at the path given, autocreate builds a world at that path: "Creates a new world if none is found. World size is specified by: 1(small), 2(medium), and 3(large)." That is the one way this move silently goes wrong. A mistyped folder, a renamed file, a .wld.zip that was never unzipped, and the server does not fail — it generates a fresh world at your carefully typed path and your players spawn on a beach with nothing built. The fix is always the same: check that the path in world= names the exact .wld you copied, and that worldname, which only names the world when autocreate makes one, is not doing a job you meant world to do. One neighbouring failure has the same shape: if -config points at a file that is not there at boot, the server falls back to asking its startup questions one by one, so a typo'd config filename reads as "my config is ignored".
Stop the server before you swap files
Copy world files while the server is stopped. The saving rules are why: "The server will auto-save the world now and then, but will only save on shutdown when using the exit command." In practice the world is saved at every dawn in game — about every 24 minutes — and, since 1.4.5.0, "Servers now save the world when the last player leaves", but closing the window or killing the process still skips the shutdown save and the last stretch of play with it. The safe sequence is the console's own: save to save the game world, then exit, which shuts the server down and saves (exit-nosave skips the save on purpose). Then copy the .wld in or out, and start the server again (Server).
Starting it, and knowing it worked
Start the server the way you usually do — start-server.bat on Windows, the binary under tmux on Linux, both covered step by step in our Terraria dedicated server setup guide. The console tells you which of the two paths you are on: a server doing what you asked names its version — "Terraria Server v1.4.5.8" — and finishes with ": Server started", while a server that fell into the autocreate trap says so first by announcing "Creating world" before that. Join the way anyone joins: Multiplayer from the main menu, pick a character, enter the server's address and port. If the join fails, the diagnosis lives in our Terraria server not connecting guide — version mismatches and unreachable ports, not the world file, are where joins break.
Downloading the world back
The move is a copy, and it works in both directions. To take the world off the server: run save and exit so the world is written, then copy the .wld out of the server's Worlds folder and into the Worlds folder on your own machine — the same paths as step 2, read backwards. Back in your game's Worlds folder, the file is a local world again, playable where you started it. Keep a copy of the old local file if one is still there rather than overwriting it, and remember the server keeps its own safety net you can also copy: worldrollbackstokeep in serverconfig.txt, default 2, "sets the number of rolling world backups to keep" — a key documented in the shipped file itself. Two copies of one world only stay one world if one of them is retired, so once the server's copy is the live one, treat your local copy as the backup (serverconfig reference).
Versions and mods around a moved world
A client and a server on different versions cannot host the same world, so before a moved world receives players, put both ends on one version — today that is the 1.4.5.8 line for the PC client and the dedicated server alike. And a modded world belongs on a modded server: tModLoader's stable is still built on Terraria 1.4.4 content, making a tModLoader server a 1.4.4-series server that current vanilla clients cannot join, and vanilla and tModLoader ends of one server cannot be mixed. The version picture per platform, and the modded-server how-to, are in our not-connecting guide's version table and the tModLoader on 1.4.5 guide.
Where to read next
Moving the world in is one step of running a Terraria server. The setup guide walks the whole install, the serverconfig.txt reference covers every key your world line sits beside, the Host & Play versus dedicated server guide explains why a dedicated server is the right home for a world that should outlast the host, the backup checklist keeps the world safe once it is live, and moving a server to a new host covers the day the whole server moves again.
If you would rather have a server that stays online without running it yourself, ForgeWorld Gaming’s Terraria Standard plans start at CA$8.99/month for 4 player slots. Your server is set up automatically after payment. Current player counts, exact prices and order status are on the Terraria availability page.