Mastodon State Historic Site
Also known as Kimmswick Bone Bed
- Status
- Status not posted
- Entrance fee
- Statewide rule — see below
- Day-use reservations
- None mentioned
- Dogs
- Statewide rule — see below
- Camping
- None listed
- Official site
- mostateparks.com(636) 464-2976
Official page last checked Oct 29, 2026. How we keep this current
Overview
Covering about 420 acres, Mastodon State Historic Site lies in Jefferson County, about 4 miles south of Arnold.
Popular activities here are ranger programs, hiking, and picnicking.
Hours
Park, gate, office and facility hours are listed separately because they often differ. Alerts above override normal hours.
| Facility | Days | Hours | Season |
|---|---|---|---|
| Park | Historic Site Grounds: 8 a.m. to half-hour after sunset, daily, year-round | ||
| Visitor center — Museum | Wed–Sat | 9 a.m. – 4:30 p.m. | — |
| Sun | noon – 4:30 p.m. | — | |
| Thu–Sat | 11 a.m. – 4 p.m. | — | |
| Sun | noon – 4 p.m. | — | |
| Office | Mon–Sat | 9 a.m. – 4:30 p.m. | — |
| Sun | noon – 4:30 p.m. | — | |
Official wording
Historic Site Grounds: 8 a.m. to half-hour after sunset, daily, year-round
Museum: March 16 through Nov. 15 Museum closed Monday and Tuesday 9 a.m. to 4:30 p.m. Wednesday through Saturday Noon to 4:30 p.m. Sunday (closed Easter Sunday) Nov. 16 through March 15 Museum closed Monday through Wednesday 11 a.m. to 4 p.m. Thursday through Saturday Noon to 4 p.m. Sunday
Historic Site Office Hours: 9 a.m. to 4:30 p.m., Monday through Saturday Noon to 4:30 p.m., Sunday (closed Easter Sunday) Please note there will be times when the office is temporarily closed while staff are working on the grounds. The office telephone is monitored for messages during office hours.
2025-2026 State Holidays: On the following days (actual or observed), staff will not be available and site buildings will be closed: Thanksgiving Day; Nov. 28, 2025; Christmas Eve; Christmas Day; New Year’s Eve; New Year’s Day; Martin Luther King Jr. Day; and Washington's Birthday.
Source: official park page, checked Oct 29, 2026. Times are local to the park (America/Chicago).
Pets
Pets welcome; leash no longer than 10 feet at all times; no more than two dogs per campsite recommended; pets not allowed in buildings (except Cabins for Canines units), public swimming areas or waters reserved for fishing.
Statewide rule from Missouri's park system (source). This park’s page doesn’t state its own pet rules, so check for local restrictions.
Fees and passes
Fees apply to camping, lodging and some tours (e.g. cave tours).
Statewide fee rule from Missouri's park system; this park’s page doesn’t list its own fees.
Reservations
- Day use
- No day-use reservation requirement mentioned
- Booking system
- Missouri State Parks reservation system (UseDirect / Tyler, 'ICampMO')
- Phone
- 877-422-6766 (877-ICampMO)
We link to the official booking system rather than showing live availability, which changes minute to minute.
Things to do
Ranger and interpretive programsHikingPicnicking
Trails
| Trail | Length | Difficulty | Notes |
|---|---|---|---|
| Limestone Hill Trail | — | — | — |
| Spring Branch Trail | — | — | — |
| Wildflower Trail | — | — | — |
Trail descriptions from the park
Below is a list of designated trails at this site.
Limestone Hill TrailSpring Branch TrailWildflower Trail
- Trail Map
- Trail Information
- Trail Map
- Trail Information
- Trail Map
- Trail Information
Amenities
Facilities
- Picnic areas
- Playground
✓ listed by the park · ✕ the park says it is not available. Anything not shown here isn’t mentioned by the official source — that means unknown, not unavailable.
Accessibility
Birding
Visitors of all abilities can enjoy birding along Spring Branch Trail. This trail has information and signage, rest areas, mostly manageable surfaces, and many other ADA considerations.
To find additional locations that are accessible, visit Birdability to view their accessible birding trails maps.
Museum
Two paved parking spaces are designated for people with disabilities and are set at an average 0% slope directly in front of the museum. Crosswalks are marked from the parking spaces to the museum entrance pathway. Per ADA standards, the handrail-lined ramp is made up of several 12-foot ramp sections separated by landings. The entrance is level with easy-to-open doors. Inside the entrance to the right is an information desk where staff take admission fees and offer books, postcards, T-shirts and mementos for sale.
Read more from the park
To the left of the entrance is an accessible water fountain. Around the corner are the men’s and women’s restrooms, both of which have lever-handled lavatory faucets, an accessible baby-changing table and front-transfer toilets.
Exhibits include glass cases, wall-mounted panels and hands-on specimens. All exhibits have interpretive panels. A video with closed captioning available is shown in the auditorium. Interpretive programs are available for organized groups by reservation.
Wildflower Trail
The trailhead is located near the top end of the reserved parking. Here, a kiosk provides site information and an accessible water fountain is located nearby. The paved portion of the trail becomes very steep and ends at the lower museum door, which cannot be used from the outside. From here, a gravel back-filled flagstone trail continues with a rope railing. Reaching the bluff, a series of railed steps interspersed with stretches of fine-gravel lead to the bottom. The trail continues in gravel fines through the bone beds and in a loop up the slope, past a historic quarry and back to the trailhead.
Day-Use Area
- Parking
Paved, accessible parking spaces are found throughout the day-use area.
- Picnic Shelter
A paved pathway leads to the picnic shelter, which provides extended-end tables, a group grill and horseshoe pits with a base of packed gravel fines. Nearby are an accessible water fountain and a playground.
- Spring Branch Trail
This 0.5-mile-long trail is level with a packed base of gravel fines or earth and is considered accessible. Fair weather should find the base solid. Level access can be found by going past the shelter house.
- Picnic Sites
Two accessible sites are available and provide a paved pathway and pad, an extended-end table and a pedestal grill.
- Restroom
From approximately April 15 through Oct. 15, an accessible flush restroom is available and is accessed on a level, paved sidewalk. From approximately Oct. 15 through April 14, an accessible vault toilet is available, which is accessed along the same sidewalk. An information board and water fountain is located along the path for your convenience.
Special-Use Area
The special-use area has not been modified for accessibility.
For more information, contact the historic site:
Mastodon State Historic Site
1050 Charles J. Becker Drive
Imperial, MO 63052-3524
636-464-2976
1-800-334-6946
1-800-379-2419 TDD
Last updated: December 2023
Official accessibility information
Conditions change. Contact the park to confirm specific accessible features before your visit.
Getting there
- Address
- 1050 Charles J. Becker Drive
Imperial, MO 63052-3524 - Nearest town
- Arnold — about 4 mi south (straight line)
- Coordinates
- 38.3783, -90.3935
- Phone
- (636) 464-2976
Nearby state parks
Sources and freshness
- Missouri State Parks — park page — last checked Oct 29, 2026
- Quick List of Parks and Historic Sites (HTML) + MoDNR ArcGIS boundary layer for coordinates
- Wikidata
“Last checked” is when our system last read the official source. No change has been detected since this page was first published. Hours, fees and rules can change without notice — confirm with the park before you go. Methodology