Rainbow trout are native to the Pacific Ocean watershed of North America, including rivers, lakes, and streams in Alaska, western Canada, and the western United States. However, due to their popularity as a game fish, rainbow trout have been introduced to waterways all around the world, including South America, Europe, and New Zealand. In the wild, rainbow trout prefer clear, cool streams and rivers with gravel bottoms where they can lay their eggs. They also thrive in lakes and reservoirs that provide ample food and shelter. When rainbow trout are introduced to new habitats, they can quickly adapt and establish themselves, making them a common and popular fish in many areas of the world.