GeoJSON is a format for encoding geographic data structures using JavaScript Object Notation (JSON). It allows users to represent various types of geographic features, such as points, lines, and polygons, along with their associated properties. This makes it easy to share and visualize spatial data on web applications. GeoJSON is widely used in mapping and geographic information systems (GIS) because it is lightweight and human-readable. It supports various coordinate reference systems and can be easily integrated with web mapping libraries like Leaflet and Mapbox. This versatility makes it a popular choice for developers working with location-based data.