What is the name of the box that provides greater detail of a specific area on a map, such as Nairobi on a map of Africa?

The term that describes the small box or additional area on a map that provides greater detail of a specific region, such as Nairobi on a map of Africa, is referred to as an inset. An inset map offers a focused view, allowing for a more detailed representation of an area that may be too small or densely packed to be effectively displayed at the same scale as the main map. This allows map readers to locate and understand key features or important information about that particular area, which might otherwise be overlooked in the broader context of the larger map.

In contrast, a legend explains the symbols and colors used on the map, an index is typically a list of places or features included in the map, often with corresponding page numbers or map coordinates, and a margin usually refers to the blank space around the edges of the map. These elements serve different purposes and do not specifically provide detailed information about a small area like an inset does.