2 documented waterfalls in Illinois, when each one actually runs, and what the river is doing right now where a gauge exists.
Trail status, closures and safety rules belong to each falls' managing agency, named and linked on every page.
Each card carries the typical big-water window drawn from the falls' actual driver, and the latest USGS reading on its feeding river where a gauge exists. The full page for each falls explains the season, shows today against the USGS percentile band, and quotes the managing agency on access.
The tallest of Starved Rock's canyon falls, with an agency that publishes the flow calendar outright: falls run March through June, may dry out by late June, and return as January icefalls.
The Shawnee Hills' wet-weather cascade at the edge of its namesake wilderness, small but very scenic in the Forest Service's words, and best caught within days of rain.
Live readings: USGS Water Services (National Water Information System). Instantaneous values and daily statistics services. U.S. Geological Survey data are works of the United States Government and are in the public domain.
Most of Illinois's documented falls run on rain, so they answer to the last few storms rather than to any fixed date. The mix here is all 2, and none of them sits on an active USGS gauge, so these pages run on seasonal climatology and the managing agency’s own words.
Windows are typical-year climatology from each falls' driver, not forecasts. Live readings and percentile bands are USGS data, public domain; where a page says a river is above or below typical, that comparison is ours and is labelled. Access and safety belong to each falls' managing agency, named on its page. National picture →