What Is Terraforming in ACNH?
Terraforming is the most transformative feature unlocked in Animal Crossing: New Horizons. Once you achieve a 3-star island rating, Tom Nook gives you access to the Island Designer app, which lets you reshape your island at a fundamental level — carving new rivers, building cliffs, and laying everything from stone roads to custom-pattern paths.
It's also, arguably, the most intimidating feature in the game. A single terraforming project can take real-world weeks or even months to complete. And unlike rearranging furniture, terraforming mistakes aren't easy to undo — dismantling a cliff takes as long as building one.
This guide will help you approach terraforming strategically, so the time you invest produces results you love.
The Golden Rule: Plan Before You Build
Before moving a single tile of cliff or drawing a single waterway, spend time planning your terrain in a visual tool like Happy Island Designer.
The planner uses the same grid as the game, so you can:
- Sketch multiple river route options and compare them
- Test cliff configurations without permanent consequences
- See how your terrain changes interact with building placement
- Plan bridge and incline locations before you commit to a cliff shape you can't fix
Players who terraform without planning often find themselves halfway through a project, realizing their rivers don't flow well or their cliff positions create awkward dead zones. Planning avoids this.
Understanding What You Can (and Can't) Change
What Terraforming Lets You Modify
With the Island Designer app:
- Rivers and water: Create new channels, widen water, add ponds, remove water
- Cliffs: Build up or tear down elevation, up to 3 levels high
- Paths: Lay or remove any of 9 path types anywhere on the island
What Is Permanently Fixed
Some things cannot be changed no matter what:
- Resident Services plaza — fixed to its original location
- Airport — fixed in one corner of your island
- River mouths (where rivers meet the ocean) — cannot be moved
- Secret beach — the small rear beach is permanent
- Beach rocks and the wooden pier — fixed positions
Always account for these fixed elements when planning your terrain overhaul.
River Design: Making Water Look Natural
Rivers are often the first thing players want to redesign — and the area where the most common mistakes happen.
What Makes a River Look Unnatural?
- Perfectly straight lines: Real rivers meander. A straight channel looks like a ditch.
- Uniform width: Natural rivers narrow and widen as they flow. A perfectly constant width looks artificial.
- 90-degree corners: Sharp right-angle turns feel mechanical, not geological.
Tips for Natural-Looking Rivers
Curve and meander Draw your river channel in a gentle S-curve or a slow winding path. Use diagonal tiles at corners to soften turns.
Vary the width Let the river widen slightly in some sections (like a natural flood plain) and narrow in others (like it's squeezing between elevated ground).
Add connected pools Small pond areas connected to the main river — or slightly offset side channels — give the impression of a more complex waterway system.
Create islands A small island in the middle of a river is one of the most photogenic terrain features you can build. Accessible by bridge, or left wild.
Leave the banks alone Don't fill every inch of riverbank with furniture or paths. Some bare shoreline with weeds, flowers, and shells looks far more natural than a perfectly manicured canal.
Waterfall Tips
Waterfalls are created wherever a cliff edge meets a body of water. Key things to know:
- Any cliff height works: You can have a waterfall tumbling from level 1, 2, or 3
- Multi-tier waterfalls: Stack two or three waterfall levels for a dramatic cascade
- Corner waterfalls: Diagonal cliff edges next to water create stunning angled falls
- Width matters: A waterfall that's 2–3 tiles wide is more impressive than a single-tile trickle
- Sound design: Waterfalls create ambient sound — useful for making certain areas feel like living spaces
Cliff Design: Thinking in Elevation Levels
ACNH supports up to 3 cliff levels above ground (plus ground level itself). Most players use 2 levels for the majority of their island and reserve the third level for special features.
Planning Your Elevations
Before you start building cliffs, decide on your elevation philosophy:
Plateau style: One or two large flat elevated areas (easy to build on, visually simple)
Terraced style: Multiple stepping levels descending from a high point (visually complex, more natural-feeling, harder to navigate)
Natural irregular style: Uneven shapes with rounded edges, varying widths (highest visual quality, hardest to plan)
Fortress style: Rectangular enclosed elevated areas (satisfying geometric look, works well for towns or castle themes)
Cliff Edge Aesthetics
How you shape the edge of a cliff matters as much as its position:
- Straight edges look architectural and intentional — good for urban or structured themes
- Rounded/diagonal edges look natural and organic — good for nature themes
- Mix of both creates the most interesting terrain — some geometric, some natural
The diagonal cliff tools are underused. Experiment with them on your planner to see how much softer and more natural curved cliff edges look compared to right-angle corners.
Cliff Mistakes to Avoid
Cliffs that trap you Every elevated section needs at least one incline to reach it. You only have 8 inclines total. If you build a large cliff structure with multiple isolated platforms, you can run out of inclines and leave sections permanently inaccessible.
Cliffs that block river access If you want to put a waterfall somewhere, make sure your cliff design includes river water reaching that level. Planning these two things together on the digital planner avoids contradictions.
Cliffs too close to fixed elements You cannot build cliffs directly adjacent to Resident Services or too close to the airport. Always check your spacing on the planner before committing to cliff placement near fixed buildings.
Path Planning: Connecting Your Island
Paths define your island's "skeleton" — the navigational structure that ties everything together.
Available Path Types
The Island Designer includes 9 path types:
| Path Type | Best Used For |
|---|---|
| Grass | Natural trails, countryside |
| Dirt | Farm areas, hiking trails |
| Stone | Town squares, traditional streets |
| Brick | European-style neighborhoods |
| Sand | Beach areas, resort vibes |
| Dark Dirt | Forest areas, shadowed paths |
| Arched Tile | Modern city streets, geometric design |
| Wooden | Japanese gardens, docks, natural bridges |
| Terra-cotta | Mediterranean or warm-weather themes |
Path Design Principles
Design your main road first Your "main road" is the path you'll walk every single day — from the airport to Resident Services, from there to the shops, to the residential area. This should be obvious, easy, and well-paved.
Secondary paths for secondary areas Paths to villager homes, the museum, and scenic areas can be narrower or in a different material. Variation in path width and material signals hierarchy.
Leave some unpaved ground An island where every inch is covered in paths is exhausting to look at. Intentional grassy patches, especially around trees and flower beds, create breathing room.
Mix materials intentionally Using stone for your main road and dirt for nature trails, for example, creates a visual system that's intuitive to read. Using random path materials everywhere feels chaotic.
Use borders A border of a different path material (or no path at all) between zones is an effective and low-effort way to define transitions between areas.
Space Management: Working Within Your Island's Limits
Your island is roughly 240 × 192 tiles — that sounds large, but gets used up faster than expected once you account for rivers, cliffs, beaches, and fixed buildings.
Maximize Vertical Space
Cliffs let you effectively increase the usable area of your island. An elevated plateau isn't just visually interesting — it's additional space for buildings, gardens, or personal retreats that might otherwise crowd your ground level.
Plan for Buildings First, Paths Second
Don't lay out your full path network and then try to fit buildings into the remaining space. Place all buildings first (digitally, in your planner), then draw paths to connect them.
Common Space Mistakes
- Rivers that are too wide: A 3–4 tile wide river sounds modest, but takes up significant island real estate. Use width variation rather than consistent maximum width
- Oversized cliff sections: A single massive plateau sounds dramatic but often wastes space. Multiple smaller elevated sections are usually more useful and visually interesting
- Paths running through future decoration spots: Plan where you'll put outdoor furniture clusters and make sure paths route around them, not through them
- No space between buildings and terrain: Terrain changes too close to buildings can block placement and look cramped
Advanced Terraforming Techniques
Diagonal Cliff Edges
Using the corner cliff tool creates slanted edges that look dramatically more natural than right angles. Rotate between standard and diagonal cliff pieces to sculpt organic-looking terrain.
Hidden and Surprise Areas
One of the most rewarding terraforming uses is creating areas that feel discovered:
- A small garden behind a cliff face, accessible only via a single incline
- A waterfall-flanked alcove that's visible from the main path but requires a detour to enter
- An elevated overlook that you don't see until you climb the last incline
Surprise areas give your island a sense of depth and reward exploration.
Layered Waterfalls
Building a waterfall that cascades across multiple cliff levels is one of the most dramatic visual effects in the game:
- Build a level-3 cliff section with water at the top
- Cut a notch in the level-2 section below it so water falls again
- Repeat at level-1
The result is a three-tier waterfall with ambient sound across all three drops. Requires careful advance planning to make sure each level has water on both sides of the fall.
Asymmetrical Cliff Design
The temptation is to make cliff sections symmetrical and neat. Resist it. Asymmetrical clips — where one arm of a cliff extends differently from the other, or a plateau is roughly but not perfectly rectangular — look far more natural and photo-worthy.
Using a Planner Before You Terraform
The single most effective practice any terraformer can adopt is using a digital planner before touching in-game terrain.
With Happy Island Designer open before you start:
- Recreate your current island layout
- Draw your desired final terrain — rivers, cliffs, waterfalls
- Place all buildings in their planned final positions
- Plan where each incline and bridge will go
- Identify any conflicts (cliff too close to a building, incline needed where there isn't space, etc.)
Fix those conflicts on the digital canvas, not in-game. Then when you start terraforming, you have a clear, tested blueprint to follow.
Frequently Asked Questions
How do I unlock terraforming? Get your island to 3 stars. Talk to Isabelle at Resident Services to check your rating and get feedback on what to improve.
Can I undo terraforming? Not with an undo button. You have to manually reverse any changes. This is why planning first is so important.
How many inclines and bridges can I have? You can have a maximum of 8 inclines and 8 bridges. Plan carefully.
Can I terraform the beach? You can add and remove sand path on the beach, but you cannot change the actual beach tiles or their elevation. The shoreline shape is fixed.
Does terraforming affect villager dialogue? No. Villagers will comment on your island, but terraforming itself doesn't change their move-in or move-out behavior.
How long does a full island terraforming take? It varies enormously. Minor river rerouting might take a few hours. A complete island overhaul with new cliff structures and river systems can take several weeks of daily play. Plan big projects in phases.
Conclusion
Terraforming is the highest-leverage creative tool in Animal Crossing: New Horizons. The terrain you build literally defines the world your island exists in — where rivers flow, how elevation creates drama, what parts of the island feel grand versus intimate.
It's also deeply satisfying. There's a particular joy in standing on a cliff you shaped yourself, looking down at a river you designed, knowing the path you built connects that waterfall to the town square below.
Plan carefully. Build in phases. And when in doubt, go back to your digital planner and adjust before you ever start digging.
Ready to plan your terrain? Open Happy Island Designer and start sketching.
Related reading: