Cities: Skylines is an endlessly replayable game. Players can design different cities on the same map tiles, purchase different tiles on the same map, play on different maps, play special scenarios with unique requirements, and download DLC and player-designed mods that add even more to the game.
If all of that isn't enough, players can also create their own maps and scenarios, either to play them or to share them online as a way to challenge others or show off their skills. This guide will go over the basics of how to design a custom map in Cities: Skylines and then how to play with it.
The Map Editor
The editors are all available on the main menu, and the map editor is the first one on the list. The theme editor lets players adjust colors and textures to create new visual and cultural themes, the asset editor lets players preview their asset creations in the game engine and assign them random colors, and scenario editor lets players add triggers and conditions to an empty map or an existing city.
When players first open the map editor, they start by choosing a visual theme. This can be one of the built-in themes, a theme from an expansion, or a theme from a mod. After that, they get a blank canvas in the form of an empty grass plain that's 9x9 squares big.
Players should keep in mind that the standard play area is the 5x5 grid in the middle of the map, and while the beginning tile is at the very center by default they can choose any of the playable tiles to be the starting point. The 56 tiles outside of the 25 in the middle are there for decoration only, and the only way to interact with them during a game is by getting a mod that unlocks them.
Something else that appears at the start is a list of requirements and recommendations. For a map to support a game of Cities: Skylines, players must make sure that an incoming and outgoing highway connection sits somewhere in the central square, and they must make sure that water flows through at least part of the square. Without these, a Cities game will end before it can begin.
The Chirper list also has a set of recommendations. These aren't required, but they give players more options and can support a more diverse set of city designs.
Making Connections
To build the all-important off-map connections, players can use the road tool to build highways, railroads, and other routes. Note that the map editor can only create highways and not any other kind of road. Ideally, players should build highways in pairs, with one road going in each direction. However, there's nothing to stop a player from building one-way highways or highways that start together and go off in different directions.
Regardless, a highway should eventually reach the edge of the map and then go beyond it. Players can do this by building a road that goes all the way to the edge and can't go any farther. If it's built correctly, players should see a green arrow where the road ends. This is where vehicles will spawn in when they enter the map and despawn when they leave. Players can create up to 4 incoming and outgoing connections for highways, which amounts to two long highways that stretch from one edge of the map to the other.
Players can then do the same thing for railroads, ships, and airplanes. Railroads work the same way as highways (including the limit of four outside connections), but the plane and ship paths are dotted lines that are normally invisible. Ships and planes will enter from an outside connection, follow the dotted line, and then exit to another outside connection. However, they'll detour to visit a seaport or airport if it's in the same square as the one they're crossing.
Land and Sea
Designing a map with an interesting shape and functioning water sources is probably the hardest part of editing. Players get the same landscaping tools that they can use while playing the game, but the map versions are much more powerful (and don't cost any money). The map tools also come with a few different brush shapes that can make terrain features look a little more random and natural.
Of course, not everyone is great at 3D sculpting, which is why the game allows players to import height maps. Players can find these assets online, and there are several websites that let users create height maps using real topographical maps.
The other tricky part is in setting water sources to create flowing rivers. Players need to set a sea level that applies to the edges of a map, and they need to set down water sources that will generate rivers without flooding the whole map. The best way to do this is to create a deep lake with a river channel that slowly drops lower as it crosses the map. Players can set the strength of a water source by clicking and holding and then pulling up or down. Water sources will try to flood their surroundings until they reach the top of the source's disc, so never set them higher than the banks of the river or lake they sit in.
One last thing players should do is unpause the simulation. The game's water physics only work while time is passing, so unpausing is the only way to see if they work right. Also, while players can see how water flows normally, the only way to see the arrows that show current direction and strength is to select the ship path tool.
Natural Resources
One last thing players should do for their map is create areas full of ground resources. Players can choose a resource type, increase the brush size, and then create large pockets of ore, oil, and fertile land. While painting resources, keep in mind that the outer ring normally isn't used and players can only buy 9 of the inner 25 map tiles. It's a good idea to create multiple areas of all three resources, at least if players don't have a specific challenge in mind.
The fourth natural resource is forests, and this one gets its own section because trees are both a resource and a decoration. Players can dot the landscape with trees to make an interesting map, but only a dense woodland counts as a forestry resource. Something else players should be aware of is that forests can't overlap with fertile land and ore can't overlap with oil.
Once players are happy with what they've created, they can save their map. The map needs a file name on the left and a name for the map itself on the right, and don't forget to select the option "Publish Map in New Game Panel." With all that done, players can choose their custom map when starting a new game and they can share their map on Steam Workshop (at least if they bought their copy through Steam).
Cities: Skylines is available now on PC, PS4, PS5, Switch, Xbox One, and Xbox Series X/S.