On Instagram, the creator search has a unified Location filter with two modes: the classic mode searches by fixed country and city terms, while the map mode lets you pick a point on the map (or search for a place with auto-complete) and search around it with a radius. The default radius is 50 km; you can adjust it from 1 km up to 1,000 km.
If you select an entire region on the map instead of a point, the radius is disabled — the rectangle on the map then marks the region's boundaries. To use a custom radius again, click a specific point on the map. In the dedicated Content search, the Location filter matches the location tags in the posts themselves (country, city, region or even landmarks like the Eiffel Tower), so you find content that was actually posted from that place.