The west end of the island is not natural ground

The island

Cayuga Island sits in the upper Niagara River in the LaSalle section of the City of Niagara Falls, Niagara County. It covers about 140 acres — roughly a mile and a quarter long and a third of a mile wide. The Niagara River runs along its southern side; a narrower channel called the Little River, or Little Niagara River, separates it from the mainland to the north. It is a residential neighbourhood with a city park.7

It also carries one of the older stories in the region: the island is believed to be where La Salle’s men built Le Griffon in 1679, the first sailing ship on the upper Great Lakes. A commemorative rock on the mainland shore at Griffon Park marks it.7

Two episodes of filling

DEC’s account is short and specific: the western end of Cayuga Island “was extended in the early 1900s and again between 1958 and 1962 using fill that included industrial material.”1

The Niagara Gazette adds scale and sourcing that DEC’s public documents do not. It reports the western end was extended approximately 240 yards into the Niagara River, and that fill and industrial material came from several private companies.45

The newspaper’s dates do not match DEC’s, and do not match each other. Its 15 June report gives 1960 to 1982; its 20 June report gives 1950 to 1980; DEC gives 1958 to 1962 for the second episode.541 We use DEC’s range and flag that filling may have continued later than the agency’s public summary indicates.

The most-asked question, answered carefully

Who is named in the record

This is where a story like this usually goes wrong, so the framing here is deliberate and narrow.

DEC has not publicly named a responsible party for the Cayuga Island site. Across both 2026 fact sheets the agency’s language is consistent and impersonal: “fill that included industrial material,” “contaminants related to industrial material.” No company appears in either document.1

Five companies are named in reporting by the Niagara Gazette, which describes fill and industrial material as reportedly sourced from them. That is a journalist’s account of the historical record, not an agency finding, and not a legal determination.54

The nearest comparable record

What Griffon Park tells us, and what it does not

Across the Little River from the island, on the mainland at roughly 9347 to 9551 Buffalo Avenue, sits Griffon Park: a 10.5-acre city park with a boat and kayak launch and the commemorative Le Griffon rock.7 DEC also carries it as remediation site 932081, and its file is far older and thicker than the island’s — a Phase I report in 1988, a two-volume Preliminary Site Assessment in 1993, and work under the state’s Inactive Landfill Initiative in the 2020s.8

The Inactive Landfill Initiative is DEC’s programme for investigating closed and suspected landfills for impacts to groundwater and drinking water sources.13 Between 23 February and 23 March 2022 its contractor installed, developed and sampled five new monitoring wells at Griffon Park, and logged fill material in five borings between 5 and 17 feet below ground surface — clear and brown glass, metal, cloth, brick fragments, cinder and wood.10

That is the most concrete published description of what mid-century fill in this immediate neighbourhood physically contains, and it is why the cross-section on the previous page is drawn to seventeen feet. But Griffon Park is a different site with a different file, on the other side of a river channel. Its boring logs are not the island’s boring logs.

One more detail is worth noticing. Griffon Park’s DEC classification is N — No Further Action — and DEC nonetheless collected soil, sediment and groundwater samples there in June 2026, posting an analytical report in July.211 A classification is a status, not a conclusion that stops.