Located at the coast of Jianlu Village, Shimen Arch is a famous tourist attraction site in Shimen District. Once a small hill formed from piling of andesite rocks and debris, the sea arch was created when the erosive force of ocean waves breaks through its bottom. Marveling at the arch-door-shaped structure of the sea arch, early settlers during Qing Dynasty named this area "Shimen", which literally means "stone arch door". After retrocession of Taiwan from Japan, the name "Shimen" was adopted as the district name of the area, and Shimen District has since become the northmost administrative district in Taiwan.

Because sea arches are formed by coastal erosion, Shimen arch should have been located at around sea level. However, due to permanent land uplift, Shimen Arch is now above 2m above sea level and no longer affected by erosive force of sea water; the sea arch therefore gets to remain in its current state. Various plants grow abundantly on top of Shimen Arch while the exposed rock wall on the side reveals its formation level. Tourists visiting here can not only find many interesting stones in various sizes and shapes but also observe a variety of geological structures.

The establishment of a ferry pier near Shimen Arch added more attraction to the area recently. Transportation Department has proposed a development project worth 200 millions in investment as the effort to promote development of industries and tourism in Shimen District.