The US Congress codified the National Historic Preservation Act of 1966 (NHPA), the nation’s most effective cultural resources legislation to date, mostly through establishing the National Register of Historic Places (NRHP). The NHPA requires federal agencies to address their cultural resources, which are defined as any prehistoric or historic district, site, building, structure, or object. The precursor to the Corps of Engineers erected the mole (a.k.a., the south pier) in the early 1820s at the entrance to the Buffalo harbor. The area on top of and surrounding the mole was modified through the past two hundred years, many of the character-defining features remain including the stone retaining walls, talus, stairs, and lighthouse identified in plans and drawings from the period of construction. Notably lost is the stone tow path, or banquette, and the stone incline on the south side of the mole is no longer visible. The researchers recommend a period of significance of c. 1820 through 1972 (50 years) since the mole has continued its original use of keeping the entrance to the Buffalo River open for freight and recreational boating traffic through the present day.