Photo: David Wilson from Oak Park, Illinois, USA · CC BY 2.0Great Falls of the Illinois River
If you're passing
Is it plungeworthy?
A dam on Illinois River.
The details
- Type
- Dam
- Watercourse
- Illinois River
- Coordinates
- 41.32354, -88.70843
About Great Falls of the Illinois River
Great Falls of the Illinois River is a dam in Illinois, on Illinois River.
It's fullest after rain, and flow can drop off during dry spells — plan around recent weather.
Plungeworthy rates Great Falls of the Illinois River 4.1/10 — if you're passing. The score weighs its scale, how confidently it's mapped, and its character.
What you'll find
Know what this listing is: the Great Falls of the Illinois River is not a waterfall. It's a two-mile reach of fast water near Marseilles where the river drops about three feet total — a gradient of eighteen inches per mile. Historic and hydrologically real; a plunge it is not.
Don't confuse it with the 24-foot drop at the Marseilles Lock and Dam nearby — that's a navigation dam, engineered, and not this feature either.
The honest way to enjoy it: Illini State Park sits on the reach's north edge — 510 acres of riverfront, camping, and the sight of a big river in a hurry. Worth a stop as exactly that.
Getting there
- Trailhead
- Illini State Park, 2660 E 2350th Road, Marseilles
- Parking
- Park lots
- Road
- Paved
- Heads up
- The 'falls' is a rapids reach viewed from the bank, not a destination drop.
When to go
Any season — high river in spring is the most dramatic water.
Rules & fees
- Fee / pass
- Free
- Dogs
- Leashed
- Camping
- Illini State Park, $12-55 a night
Researched from TopoZone — Great Falls of the Illinois River. Conditions change — verify before you drive. Been to Great Falls of the Illinois River recently? Post a conditions report below.
Where it is
Before you go
The pin marks the feature, not a trailhead or a legal route in. Some sit on private land or need a real hike, and conditions change with season and rain. Check local access, don't trespass, and never enter water — hot or cold — where it isn't safe.
Common questions
Where is Great Falls of the Illinois River?
Great Falls of the Illinois River is a waterfall in Illinois, at 41.32354, -88.70843.
Is Great Falls of the Illinois River worth visiting?
If you're passing — Plungeworthy rates it 4.1/10.
Gear for the trip
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