topographic map drawn in 1820 shows the shoal, named there as "Bajo Scarburo," as a constituent part of Sambalez (Zambales province).[38] During the 1900s, Mapa General, Islas Filipinas, Observatorio de Manila, and US Coast and Geodetic Survey Map include the Scarborough Shoal named as "Baju De Masinloc."[39] A map published in 1978 by the Philippine National Mapping and Resource Information Authority, however, did not indicate Scarborough Shoal as part of the Philippines.[40] Scholar Li Xiao Cong stated in his published paper that Panacot Shoal is not Scarborough Shoal, in the 1778 map "A chart of the China Sea and Philippine Islands with the Archipelagos of Felicia and Soloo", Scarborough shoal and 3 other shoals Galit, Panacot and Lumbay were all shown independently. Li also pointed out that thethree shoals were also shown on Chinese maps which were published in 1717.[41]

In 1957, the Philippine government conducted an oceanographic survey of the area and together with the US Navy force based in then U.S. Naval Base Subic Bay in Zambales, used the area as an impact range for defense purposes. An 8.3 meter high flag pole flying a Philippine flag was raised in 1965. An iron tower that was to serve as a small lighthouse was also built and operated the same year.[42][43] In 1992, the Philippine Navy rehabilitated the lighthouse and reported it to the International Maritime Organization for publication in the List of Lights. As of 2009[update], the military-maintained lighthouse is non-operational.[44]

Historically, the Philippine boundary has been defined by its 3 treaties,[45][46]Treaty of Paris (1898),