River

River is a common aquatic biome found throughout the Overworld, cutting across virtually any land biome regardless of temperature or humidity. Its shape and position are determined by peak-valley (PV) noise values, which causes the River to wind naturally around elevated landmasses. Occasionally, the PV noise produces loops tight enough to enclose no land at all, resulting in small isolated pools rather than a continuous waterway. In colder temperature zones, the standard River gives way to its frozen counterpart instead.

The water within a River sits at sea level and remains still. The floor beneath is composed of patches of dirt, clay, sand, and gravel, typically draped in seagrass. Any dry land that rises above the waterline is covered in grass blocks, sometimes with scattered bushes. Neighboring biomes often bleed their own features across the border — for example, oak trees from a wooded badlands biome may appear along the edge. Sugar cane and firefly bushes frequently line the banks due to the extended shoreline that River biomes naturally create.

No fully passive mobs spawn natively in the River, though animals from surrounding biomes commonly wander in. Drowned, salmon, and squid are the natural aquatic spawns within the water. In Bedrock Edition, hostile mobs do not spawn above the water surface. Overall, the River functions as a recognizable natural boundary separating different biome variants on either side of its banks.