National park · United States
Cahokia Mounds State Historic Site
Go for a half day: free entry, grounds open 8:00–dusk every day, Monks Mound's 154 steps take 15–20 min. Start before 10:00 in summer; the Interpretive Center is closed Mon–Tue.Go for a half day: free entry, grounds open 8:00 AM–dusk every day, Monks Mound's 154 steps take 15–20 min. Start before 10:00 AM in summer; the Interpretive Center is closed Mon–Tue.
Map to the park
Add your hotel to get directions from it. · stays in this browser; shared with the pocket card.
Area
9 km²3 sq mi
approximate
Established
1925
Best months
Apr–May, Sep–Oct
UNESCO
World Heritage
Rules in force · 7Crossing between the US, Canada and Mexico by land needs …Cannabis is legal in Canada and in many US states, but ta…
- North America ↗Crossing between the US, Canada and Mexico by land needs your passport even on a day trip; rental cars need the company's written permission to cross, and most US and Canadian rental insurance stops at the Mexican border.
- North America ↗Cannabis is legal in Canada and in many US states, but taking any amount across the US, Canadian or Mexican border is a federal crime — including edibles and vapes.
- North America ↗The busiest US and Canadian national parks need timed-entry, campsite or lodge reservations in summer; release dates are months ahead.
- United States ↗Check whether you need an ESTA (Visa Waiver Program) or a visa on the official CBP and State Department sites; apply only through esta.cbp.dhs.gov, not third-party sites, and allow time before you book.
- United States ↗Several popular national parks use timed-entry or vehicle reservations in peak season; check each park's page on nps.gov and book on recreation.gov before fixing your dates.
- United States ↗Medical care is very expensive for visitors; buy travel insurance with high medical cover before you fly.
- United States ↗Tipping is expected: about 15–20% at sit-down restaurants and bars, and a tip for taxis, hotel staff and guides.
At a glance
- Country
- United States
- Area
- 9 km²3 sq mi
- About 2,200 acres (890 ha) of mounds, plaza, trails and reconstructed stockade (check).
- Established
- 1925
- Best months
- Apr–May, Sep–Oct
- Permits
- For some areas
Cahokia Mounds is the largest prehistoric city north of Mexico: a Mississippian town of 15,000–20,000 people at its peak about 800 years ago, with roughly 120 earthen mounds, a flat ceremonial plaza and a rebuilt 48-post solar calendar. It sits in the American Bottom floodplain near Collinsville, Illinois, about 8 mi (12 km) from downtown St. Louis, and it is the only World Heritage site in the Midwest — run by the Illinois Department of Natural Resources rather than the federal government, which is why there is no entry fee and no national park pass involved. Most visits are a half day: the Interpretive Center film, the 154 steps up Monks Mound, and the flat walk to Woodhenge. Longer loops — the 1 mi (1.5 km) marsh and prairie walks, the 5.5 mi (10 km) Nature/Culture Hike and the 10 mi (16 km) Ten-Mile Trail — reach the quieter grassland, forest and marsh edges of the 2,200-acre site.
Decide
Why go, which months, and what lives here when
At a glance
Status
- UNESCO World Heritage · 1982The only World Heritage site in the Midwest; run by the state, not the federal government.
- Special national site · 1964National Historic Landmark; listed on the National Register in 1966.
Size and age
9 km²3 sq mi · national park since 1925
About 2,200 acres (890 ha) of mounds, plaza, trails and reconstructed stockade (check).
Why go
- The largest prehistoric city north of Mexico: 15,000–20,000 people at its peak about 800 years ago, with roughly 120 earthen mounds.
- Monks Mound is the biggest prehistoric earthen work in the Americas — 100 ft (30 m) high and 22 million cubic feet of hand-carried dirt.
- Entry and parking are free, and the grounds are open every day of the week, including when the museum is shut.
- Woodhenge, a 48-post solar calendar rebuilt on its original spot, lines up with equinox and solstice sunrises.
When to go
- JanAvoid
- FebAvoid
- MarGo
- AprBest
- MayBest
- JunCaution
- JulCaution
- AugCaution
- SepBest
- OctBest
- NovGo
- DecGo
- JanCold; occasional snow; no outdoor tours
- FebColdest stretch; museum closed Mon–Tue
- MarMild spells; equinox sunrise at Woodhenge
- AprWeekend tours resume; Indian Market weekend
- MayNature/Culture hike; Kids Day; warm
- JunHot and humid; solstice sunrise
- JulHottest, most humid; start early
- AugHeat plus Archaeology Day crowds
- SepCooling; equinox sunrise; Nature/Culture hike
- OctDry, clear; weekend tours
- NovMild; Thanksgiving Indian Market weekend
- DecCold; solstice sunrise; quiet
Wildlife and nature calendar
| What | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| White-tailed deerAll year · Common in the wooded patches; wildlife is legally protected here. | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| Turkeys and waterfowlMar–May, Sep–Nov · Ducks and other birds around the marsh and Spring Lake. | no | no | yes | yes | yes | no | no | no | yes | yes | yes | no |
| Prairie wildflowersMay–Sep · Best on the prairie loop; garden beds show plants grown here in prehistory. | no | no | no | no | yes | yes | yes | yes | yes | no | no | no |
| Ticks and mosquitoesMay–Sep · Worst on the long grass loops; repellent and long socks help. | no | no | no | no | yes | yes | yes | yes | yes | no | no | no |
Arrive & move
Getting in, how the park is divided, and where things are
How to get there
From Downtown St. Louis
I-55/70 across the Poplar St. Bridge to Exit 6 (Hwy 111), south then left on Collinsville Rd; the center is about 1.5 mi (2.5 km) on the right.I-55/70 across the Poplar St. Bridge to Exit 6 (Hwy 111), south then left on Collinsville Rd; the center is about 1.5 mi (1.6 mi) on the right.
20–30 min
From Lambert St. Louis International Airport
I-70 East over the Stan Musial bridge, then I-55/70 to Exit 6 and the same Collinsville Rd approach.
30–40 min
From North or south St. Louis County
I-255 to Exit 24 (Collinsville Rd), then left at the light; center about 1.5 mi (2.5 km) on the left.I-255 to Exit 24 (Collinsville Rd), then left at the light; center about 1.5 mi (1.6 mi) on the left.
25–35 min
From By transit
MetroLink to Missouri Avenue in East St. Louis, then taxi; or Madison County Transit bus 18 to Black Lane and a 0.75 mi (1.2 km) walk west with no sidewalk.MetroLink to Missouri Avenue in East St. Louis, then taxi; or Madison County Transit bus 18 to Black Lane and a 0.75 mi (0.7 mi) walk west with no sidewalk.
1–1.5 h
Zones and sectors
| Zone | What is there | Access |
|---|---|---|
| Interpretive Center and Grand Plaza | Museum, film, life-size village reconstruction and the flat ceremonial plaza. | Free; center open Wed–Sun 9:00–17:00, closed Mon–Tue (check).Free; center open Wed–Sun 9:00 AM–5:00 PM, closed Mon–Tue (check). |
| Monks Mound | The 100 ft (30 m) platform mound with a stairway to the top and a view to the Gateway Arch. | Free; grounds 8:00–dusk daily; own parking lot.Free; grounds 8:00 AM–dusk daily; own parking lot. |
| Woodhenge | Rebuilt 48-post solar calendar about 0.5 mi (1 km) west of Monks Mound.Rebuilt 48-post solar calendar about 0.5 mi (0.6 mi) west of Monks Mound. | Free; grounds hours; own parking lot. |
| Outer trails and marsh | Prairie, grassland, forest and marsh on the longer loops, plus stockade reconstructions. | Free; walk any day; maps at the center or in the brochure box outside when it is closed. |
Sketch map
- 1Interpretive Center · Headquarters≈38.654, -90.06430 Ramey Street, Collinsville; start here for the film and maps.Map ↗
- 2Monks Mound · Summit≈38.661, -90.062Own parking lot; 154 steps to the top.Map ↗
- 3Woodhenge · Viewpoint≈38.659, -90.073About 0.5 mi (1 km) west of Monks Mound; parking lot on Collinsville Rd.About 0.5 mi (0.6 mi) west of Monks Mound; parking lot on Collinsville Rd.Map ↗
- 4Mound 72 · Trail≈38.656, -90.064On the cement path from the Grand Plaza.Map ↗
- 5Grand Plaza · Trail≈38.657, -90.063The flat ceremonial core between Monks Mound and the Twin Mounds.Map ↗
- 6Spring Lake marsh · Trail≈38.651, -90.068On the 1 mi (1.5 km) Marsh Walk; approximate.On the 1 mi (0.9 mi) Marsh Walk; approximate.Map ↗
- 7Collinsville · Town≈38.670, -89.984Nearest town with motels and food, about 10 min away.Map ↗
See & do
Caves, trails and wildlife, with how hard each is and whether it needs booking
Top experiences
Practical
Fees, permits, rules, where to sleep and what can go wrong
Entry fees and permits
| Item | Range | Per | Note |
|---|---|---|---|
| Entry to the site and Interpretive Center | Free | person | Free; donations accepted at the center. |
| Parking (Interpretive Center, Monks Mound, Woodhenge) | Free | vehicle | Free lots for cars and RVs. |
| Self-guided iPod tour | US$3 | device | English, Spanish and German; free cassette player also available (check). |
| Printed guidebook | US$1 | book | Sold in the gift shop; 12 languages (check). |
Ranges, not quotes: fees change without notice. Check with the park or your operator · checked Sep 2026.
Entry no permit
Public tours no permit
Geocaching permit or guide
Park rules
- Grounds hours
- Open 8:00 to dusk every day; the Interpretive Center keeps shorter hours and closes Mondays and Tuesdays.Open 8:00 AM to dusk every day; the Interpretive Center keeps shorter hours and closes Mondays and Tuesdays.
- Mounds
- Stay on paths and steps; do not climb unmarked mounds or dig anywhere on site.
- Drones
- Not allowed without permission from site management (check).check
- Wildlife
- Protected by law; watch deer and birds from a distance and do not feed them.
- Pets
- Allowed on the grounds on a leash; not inside the Interpretive Center (check).check
Where to stay
Near the park
Collinsville
Chain motels and hotels 5–10 min from the entrance, just off I-55/70.
Near the park
St. Louis
Full range of hotels 20–30 min west; pair the site with downtown sights.
Near the park
Fairview Heights and O'Fallon
More interstate-side motels 15–20 min away.
Safety
Summer heat and humidity medium
Storms medium
Winter ice on the steps low
Traffic on Collinsville Rd low
Accessibility
- The Interpretive Center is wheelchair accessible, with accessible restrooms.
- Cement paths reach the Grand Plaza, Mound 72 and other key points; large signs stand at each parking lot and along the trails.
- Monks Mound's 154 steps and the grass loops are not suitable for limited mobility; the mound's base and plaza are.
Visiting lightly
- Entry is free, so give what you can at the donation box — it funds excavation and trail upkeep.
- Stay on marked paths; the mounds are fragile earthen structures, not hills.
- Carry out everything you bring; bins are limited on the outer loops.
- Buy from Native artists at the spring, summer and Thanksgiving market weekends rather than souvenir imports.
Questions people ask
How much does it cost to enter Cahokia Mounds State Historic Site?
Nothing. Entry, parking and public tours are free, and donations are accepted at the Interpretive Center. The only paid extras are the $3 iPod audio tour and a $1 printed guidebook in the gift shop.
What are the best hikes in Cahokia Mounds State Historic Site?
For most visitors the Grand Plaza and Monks Mound walks (30–45 min each on cement paths) plus the flat Woodhenge loop cover the highlights. If you want distance, the Ten-Mile Trail crosses grassland, prairie, forest and marsh, and the 5.5 mi (10 km) Nature/Culture Hike runs twice a year with an archaeologist.
When is the best time to visit Cahokia Mounds State Historic Site?
April, May, September and October: mild temperatures, weekend public tours and the equinox sunrises at Woodhenge. July and August are hot and humid, so start before 10:00. The grounds stay open daily in winter, but there are no outdoor tours from November to March.
Is Cahokia Mounds the same as the city of Cahokia, Illinois?
No. The site is in Collinsville, about 10 mi (16 km) from the city of Cahokia. Tell taxi and rideshare drivers you want the mounds on Collinsville Rd, not the town.
Can I climb Monks Mound?
Yes, during grounds hours, 8:00 to dusk. It is 154 steps to the top and free. The stairway is steep and unshaded, and it can ice over in winter.
Do I need a reservation or a park pass?
No. There is no entry fee, no booking and no national park pass involved — this is a state-run site, not a federal park. Public tours are first-come, first-served.
How long should I spend at Cahokia Mounds?
Two to three hours covers the Interpretive Center, Monks Mound and Woodhenge. Add two to three hours if you walk the Ten-Mile Trail or join a guided hike.
Deep dive
Every source; fees and rules change, so check before you go