Stone boundary wall [c.1908- ]
According to the 2017 report cited below, the masonry boundary wall was built circa 1908 to enclose the Lai Chi Kok quarantine station (now the site of the Jao Tsung-I Academy). Remnants of the wall can still be found near the former Customs Sub-station/Guard house:
"The [Jao Tsung-I] Academy, with High, Middle and Low zones, was once surrounded by a whole granite stone wall. The stone walls one can find in the main and back entrance are those remained [sic]."
Source: "Research Study and Heritage Interpretation of Historic Relics in Jao Tsung-I Academy" (2017), https://www.jtia.hk/wp-content/uploads/2017/07/lw_paper_eng_120.pdf , at p.8 (see also p. 37 for a photo of the boundary wall remnants)