The boulder, which is the namesake of the town in which it is located, is the largest glacial erratic found atop Triassic bedrock in the state of New Jersey.

The Lenape, who referred to the boulder as Pamackapuka, used the rock as a trail marker, a location to build signal fires, and as a throne for chiefs used when presiding over meetings.

[3] Prior to the arrival of European settlers, Native Americans used the Glen Rock as a trail marker as well as a place to build signal fires.

[12] The rock served as a key marker for all colonial-era land deeds, composing one of the points used in the eighteenth-century survey of the Ramapo Tract.

Developers initially desired to destroy the boulder, though they faced public outcry from borough residents who felt that the rock had substantial historical value.

[5][10] In October of that year, work was undertaken to support the base of the Glen Rock with additional stonework and wide cement walkway was added to improve the quality of the area.

[16] The council had initially attempted to allocate $500 towards the project that February, but turned to fundraising efforts in March after they discovered that there were no contingency funds available to spend.

[16][17] The committee, with the help of the local Boy Scouts, successfully raised enough funds for the project to be completed;[18][19] the bronze plaque was subsequently installed and was unveiled at a ceremony held on May 30 of that year.

[26][27] A replica of the original sign, which contained information on the boulder's history, was created and screwed onto a seven-foot-tall pole constructed to deter vandals in 1985.