Ask most people in Darien why the forest preserve off Cass Avenue is called Waterfall Glen, and they'll point you toward Rocky Glen, the tiered stone falls a half mile in from the Bluff Road lot. That's a reasonable guess. It's also wrong. The Forest Preserve District of DuPage County named the site in 1973 for Seymour "Bud" Waterfall, an early president of its board of commissioners, the same year the district added more than 2,200 acres of surplus federal land that turned a modest holding into the 2,503-acre preserve residents drive past today. The falls were already there. The name came from somewhere else entirely.
That distinction matters less as trivia and more as a signal. Waterfall Glen is one of those pieces of local infrastructure that people who live near it think they already understand, mostly because they've seen the parking lot from Cass Avenue a hundred times. Fewer have worked out which of its three access points actually matches what they're trying to do on a given Saturday, and fewer still know why the preserve's restrooms are about to disappear for the season. Both are worth sorting out before the weather turns, because September is the month Waterfall Glen quietly resets itself.
A Dam Built by the CCC, Stone Quarried for the Water Tower
The falls themselves are a dam, not a natural waterfall, built by the Civilian Conservation Corps in the 1930s across Sawmill Creek. That's part of a longer industrial history on the site that most visitors walk right past. In the late 1800s, the Ward Brothers ran a lumber mill on the same creek, and Edwin Walker operated three limestone quarries nearby that supplied stone for the Chicago Avenue Water Tower and Pumping Station, the same water tower that survived the Great Chicago Fire and still stands on Michigan Avenue today. The quarries are gone as working operations, but several remain on the property as still-water fishing spots open to anyone 16 or older with a valid Illinois fishing license.
The land carries an older history too. Long before the CCC or the quarries, the limestone bluffs that run through the preserve, including the rise now called Signal Hill, were part of a landscape where American Indian communities lived along the Des Plaines River Valley before Jacques Marquette and Louis Joliet passed through in the 1600s. Signal Hill's name reflects its later use as a vantage point for communication across the valley. None of this is signposted in a way that jumps out at a jogger on the main loop, but informative placards do appear at points along the trail if you're paying attention.
Three Gates, Three Different Days
Waterfall Glen has three points of entry, and they don't serve the same visit.
- Northgate Road, reached from Cass Avenue just south of I-55, is the main entrance and the standard starting point for the full 9.4-mile Main Trail loop. This is where you go if the plan is distance, whether on foot, bike, or horseback.
- Bluff Road, a mile and a half further south off Cass Avenue, has the smallest lot and puts you within a half-mile walk of the Rocky Glen falls. It's the right choice for a short visit built around the waterfall specifically, but the lot fills fast because everyone else has the same idea.
- Lemont Road at 101st Street, on the preserve's east side, gets far less attention and offers a quieter way in for anyone headed toward the Sawmill Creek bluff overlook or the model airplane field in the preserve's southwest section.
The mismatch between these entrances is the most common frustration reported by visitors: people default to the Bluff Road lot because it's the one they've heard of, then find it full, when Northgate or Lemont would have gotten them onto the trail with less circling.
The preserve doesn't have a busy side and a quiet side so much as a well-known door and two that most people never try.
What September Actually Changes Here
Waterfall Glen doesn't have a single season. The Main Trail's crushed limestone surface stays walkable year-round, but what surrounds it shifts on a schedule locals learn by trial and error. Right now, in early September, the preserve's prairies are entering the window when a variety of colorful asters bloom across DuPage's forest preserves, Waterfall Glen's Poverty Prairie and Bluff Savanna among the more distinctive spots to see them given the site's roughly 740 native plant species, about three-quarters of everything that grows naturally in the county.
The bigger practical shift is coming at the waterfall lot itself. The accessible flush restrooms at Bluff Road close for the season once temperatures start dropping consistently and won't reopen until spring, though portable toilets remain available there and in other parts of the preserve through the colder months. That's a small detail, but it's the kind that changes whether a family outing to see the falls is a quick stop or requires more planning. Later in the year, once snow accumulates, the district's rangers groom sections of the trail network for cross-country skiing, alternating skate lanes and classic tracks, a use the summer hiking crowd rarely thinks about.
The Things Only Regulars Know
A few details separate a first-time visitor from someone who treats Waterfall Glen as a regular part of their week.
- Dogs are welcome, but leashes can't exceed 10 feet, and alcohol is prohibited preserve-wide, which rules out the casual picnic setup some visitors expect.
- The Tear-Thumb Trail, an early offshoot from the Main Trail near the Northgate entrance, sees a fraction of the traffic the main loop does and is easy to miss if you're not looking for it.
- The open field in the preserve's southwest corner isn't just empty grass. It's a working model airplane field used regularly by local hobbyists, worth knowing before you set up a blanket in the middle of it.
- An orienteering course near the Northgate trailhead lets visitors practice map-and-compass navigation on marked routes ranging from beginner to advanced, a detail that surprises people who assume the preserve is hiking and biking only.
- The preserve sits entirely around Argonne National Laboratory, which explains the fencing some visitors notice along parts of the eastern boundary.
How to Spend a Fall Saturday Here
If the goal is the waterfall and not much else, Bluff Road is still the right lot, just plan to arrive early on a weekend before it fills. If the goal is the full loop, or you want a shot at seeing the Des Plaines River overlook and the Sawmill Creek bluff without fighting for parking, start at Northgate and go counterclockwise, which is how the main loop is typically run. Anyone who wants a quieter morning, especially with a dog on a long walk, should try the Lemont Road entrance instead and treat the falls as a destination for a different day.
None of this requires a real estate transaction to appreciate. It's simply the difference between driving past a green sign on Cass Avenue for years and actually knowing which gate to use for what you want to do on a given weekend. Waterfall Glen has been part of Darien's daily geography since 1925, when the district bought its first 75 acres here, and it will keep being that regardless of who's living in the houses nearby. Knowing it well is one more way of actually living here, not just passing through.
If you're thinking about what's next for your own address in Darien or anywhere else in Chicago's western suburbs, Alex Abramowicz & Meredith Van Syckle bring the same kind of granular, on-the-ground knowledge to pricing, timing, and neighborhood strategy that this piece brought to trailheads. Contact us when you're ready to talk specifics.
