GeoJSON is a widely used format for encoding a variety of geographic data structures. It represents spatial features such as points, lines, and polygons using JavaScript Object Notation (JSON). In the context of Leaflet, GeoJSON allows you to display complex shapes and features on your map, such as city boundaries, routes, or collections of points. By leveraging GeoJSON, you can easily visualize external spatial datasets or user-generated data in a structured way.

When working in React with react-leaflet, you can use the GeoJSON component to render GeoJSON data directly onto your map. This approach is especially useful when you need to display features from external sources, such as files or APIs. The GeoJSON component accepts a GeoJSON object as a prop and automatically renders the corresponding shapes and features on the map. You can also style these features or attach event handlers to them, just like other Leaflet layers.