An inset map is a smaller map featured on the same page as the main map. Traditionally, inset maps are shown at a larger scale (smaller area) than the main map. Often, an inset map is used as a locator map that shows the area of the main map in a broader, more familiar geographical frame of reference.
Here, the inset changes on an interval. You can stop the interval and change the map yourself by selecting a state or union territory from the dropdown menu.