On way to army-controlled Qingshuiao towards the northeast, crossing hilltop and all the way forward, there is the Northernmost Frontier - Biegu Reef Islet (coordinates: N26°22'58.8" E120°28'34.0") near Luohanping Cape. The reef islet is uninhabited by humans for now. It pops out in low tidal hours and sinks back into the sea when tides are high.
To commemorate the Northernmost Frontier and to draw more visitors, Matsu National Scenic Area Administration set up an observatory at Houao Cape. There is also a stone inscription that says “Northernmost Frontier.” Visitors are free to take pictures with it.