Eighteen Mile Creek is not eighteen miles long. The number is a distance, not a length: eighteen miles south of the mouth of the Niagara River at Buffalo, measured along the Lake Erie shore by people who navigated by counting creeks. Four Mile, Six Mile, Eighteen Mile. The Seneca had a better name for it, Koughquaugu, and they had it first.
Before anything else, a correction, because search engines get this wrong constantly.
This is not the Superfund creek
There are two Eighteen Mile Creeks in Western New York, and only one of them is a federal cleanup site.
The other one is in Niagara County. It rises just north of Lockport, runs about twenty-six miles north through Gasport and Newfane, and empties into Lake Ontario at Olcott. In March 2012 a stretch of it north of the Erie Canal was added to the EPA's Superfund National Priorities List, with PCBs, mercury, dioxins, lead, and a long list of other things in the sediment.
The creek that runs through Hamburg is a different watercourse entirely. It rises in Concord, drains roughly 120 square miles of the Southtowns, and empties into Lake Erie at Highland-on-the-Lake in Evans. Different county, different lake, different direction. If you read a headline about Eighteen Mile Creek and contamination, check which one before you panic. Portions of the Erie County creek within Hamburg carry the opposite kind of designation: the town designated them a Critical Environmental Area in May 1992.
385 million years, exposed
The lower creek has cut a gorge about sixty feet deep, and the walls of it are a cross-section of the middle-to-late Devonian: banded shale with limestone over the top, laid down when this piece of New York sat near the equator under a warm shallow sea.
What comes out of those beds has been drawing geologists since the 1800s. Rugose corals like Heliophyllum, colonial Favosites, crinoid stems, brachiopods by the hundredweight, bryozoans, bivalves, and trilobites (Eldredgeops, the one everybody wants). The rock is Hamilton Group: the Wanakah shale of the Ludlowville Formation and the Windom shale of the Moscow Formation, roughly 385 million years old.
The Town of Hamburg's own history page describes the town as internationally famous for its Devonian fossils. That is not a local exaggeration. It is a genuinely important exposure.
Where you can actually collect
Carefully, and this matters. Collecting rules vary parcel by parcel along the creek. Much of the land above the gorge is private, the cliff faces themselves are private in places, and digging into a cliff is both trespassing and a good way to bring several tons of shale down on your head. Search loose talus and natural rockfall at the base if you're on ground you're allowed to be on, and check the rules for that specific stretch before you bring a hammer.
If you want to collect without any of that ambiguity, go to Penn Dixie in Blasdell, four miles north, still inside the Town of Hamburg. It's 54 acres of former cement quarry run by the Hamburg Natural History Society, you keep everything you find, and a 2011 study ranked it the top fossil park in the country. In 2018 it set a Guinness World Record for the world's largest fossil dig with 905 people digging at once.
The steelhead run
From mid-October into early May, Eighteen Mile Creek is one of the better steelhead tributaries on the New York side of Lake Erie. The fish come in on autumn rain, and the water is fishable through the winter whenever it isn't locked up.
Two things to know before you go. First, the main branch inside Eighteen Mile Creek County Park is catch-and-release, artificial lures only. The South Branch is not under the same restriction. Second, regulations on Lake Erie tributaries change, so confirm the current rules with the DEC rather than with a blog post. There are also marked Public Fishing Rights easements along the creek where anglers have legal access across private land.
The county park itself runs about 465 acres across both branches, with roughly five miles of trail, the sixty-foot gorge, and gates open from seven in the morning. No camping, no fires, no hunting, dogs on a leash.
Wear it
Most landmarks are things people built. This one is the opposite: a slow cut through rock that was seabed when there were no land animals to speak of, running past a village that has been here for two hundred of those 385 million years.
The Eighteen Mile Creek tee is the gorge, not a postcard sunset. It's part of the ALL America City collection, one real Western New York landmark per shirt. Hamburg's other two are the Erie County Fairgrounds and Main Street, and the rest of the region is laid out in the full town-by-town guide.
Eighteen Mile Creek County Park, South Creek Road, Town of Hamburg, New York.