Field NotesOhio
Upper Falls in the Old Man's Cave gorge, Hocking Hills, with visitors on the rocks

An independent field guide · 365 places

The field guide to outdoor Ohio

Parks and forests, ancient mounds, caves, waterfalls and back roads, with the story behind each place and where to eat and fuel up nearby.
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  • 117parks & forests
  • 64ancient mounds
  • 34waterfalls
  • 40historic sites
  • 33road trips

Old Man's Cave, Hocking Hills · Photo: Rhododendrites, CC BY-SA 4.0

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State parks & forests117 places, with cabins, campsites and trails117 places Waterfalls34 falls, with trail notes34 falls Mounds & earthworks64 ancient sites, from Serpent Mound to Newark64 ancient sites Caves & caverns12 show caverns, recess caves and rock shelters12 caves Lake Erie beaches20 public beaches, Conneaut to Toledo20 beaches Historic sites40 places, from the frontier to the Civil War40 places Road trips33 drives, from the Lincoln Highway to the Morgan Heritage Trail33 drives Oddities19 giants, ghosts and folk-art stops19 roadside stops The Buckeye TrailA 1,444-mile loop, all 26 sections1,444 miles

New to the guide?

Six places to start

One from every corner of the state, each with its full story inside.

01Old Man's CaveHocking Hills · SoutheastA gorge of waterfalls and recess caves where a hermit is said to have lived, with the park's visitor center. 02Great Serpent MoundAdams County · SouthwestA gigantic earthen snake on a hilltop over Ohio Brush Creek, built by a people whose name is still argued over. 03Brandywine FallsCuyahoga Valley · NortheastThe tallest waterfall in Cuyahoga Valley National Park, reached by an easy boardwalk with an accessible upper overlook. 04Marblehead LighthouseMarblehead · Lake ErieThe oldest continuously operating lighthouse on the Great Lakes, lit since 1821, on nine acres of limestone shoreline. 05Zoar VillageTuscarawas County · EasternA well-preserved communal village founded by German separatists in 1817, on the Ohio & Erie Canal. 06Longaberger Basket BuildingNewark · CentralA seven-story office building shaped like a picnic basket, with handles that are heated in winter.

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Lake ErieWest Virginia36 places368 places813 places135 places523 places2321 places2124 places2416 places1613 places134 places418 places182 places217 places1710 places1014 places142 places27 places76 places613 places133 places34 places414 places143 places3Harrison Lake State Park2 places22 places22 places26 places64 places4

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Parks, forests & wildlife areas

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117 parks in 7 regions
The grassed embankments of the Newark Earthworks

Newark Earthworks

Newark & Heath · Licking County · Central Ohio
The largest geometric earthworks in the world
UNESCO World Heritage Site (2023)National Historic LandmarkOhio's official prehistoric monument

Newark Earthworks · Photo: Niagara66, CC BY-SA 4.0

Directions →Official source →

Enormous circles, an octagon and a square built about 2,000 years ago, and part of a golf course until 2025.

Parts
Great Circle Earthworks, Octagon Earthworks and Wright Earthworks
Great Circle
A circle about 1,200 feet across with 8-foot walls and a moat, and the bird-shaped Eagle Mound at its center
Octagon
A 50-acre octagon joined to a 20-acre circle, with a 12-foot Observatory Mound
Alignment
The Octagon tracks the moon's rise and set over an 18.6-year cycle
Original size
About 3,000 acres; less than 10 percent survives
Recognition
World Heritage Site in 2023, part of the Hopewell Ceremonial Earthworks

The story

The Newark Earthworks were the largest set of connected geometric enclosures in the world. Built by the Hopewell culture between 100 BCE and 400 CE, they covered about 3,000 acres, and less than a tenth of that survives, in three pieces: the Great Circle, the Octagon and the Wright Earthworks. At the center of the Great Circle sits Eagle Mound, a low mound. The Octagon is a 50-acre octagon with openings at all eight corners, joined to a 20-acre circle by parallel walls, and an Observatory Mound stands in the gateway between them.

In 1982, physicist Ray Hively and philosopher Robert Horn showed that the Octagon encodes the rising and setting of the moon over an 18.6-year cycle. The state named the Newark Earthworks its official prehistoric monument in 2006, and in 2023 the site became part of Ohio's first UNESCO World Heritage Site, the Hopewell Ceremonial Earthworks.

Related sites

Visiting information you can trust

Content last reviewed
September 2026 — this is when Field Notes Ohio's content was last checked, not a live status.
Primary official source
Official page
Location confidence
Verified entrance or visitor center
Published coordinates
Check current conditions
Official conditions or closures
Reservations or tickets
Tickets or admission info

Prices, hours, closures, campsite availability and trail conditions shown elsewhere on this page are not live — always confirm with the official source before you go.

The Moon's 18.6-Year Doorway

Every 18.6 years, the moon rises directly through a passageway at the Octagon. The builders laid out eight gateways and walls to mark the extreme moonrises and moonsets of that long lunar cycle, a calendar for a people who watched the sky for decades at a time.

Then, for a century, nobody could walk in. The Ohio militia camped on the Octagon in the late 1800s as Camp McKinley and helped save it. From 1910, the Moundbuilders Country Club leased it as a golf course, and for years visitors saw the moon-marking mounds between the greens and fairways.

Behind the legend

The lease is a documented story. The Ohio Historical Society leased the Octagon to the country club, and a lease that ran into 2078 was finally bought out by the Ohio History Connection, which took control on January 1, 2025 and opened the site to the public daily during daylight hours. The alignment, first described in 1982, is now accepted as a design feature of the Octagon.

The Newark Earthworks, together with Fort Ancient and the Hopewell sites near Chillicothe, make up the eight sites of the Hopewell Ceremonial Earthworks, inscribed by UNESCO in 2023.

If you go

Walk the Octagon, look for the Observatory Mound and imagine the moonrise. Then visit the Great Circle and its museum, and drive to Alligator Mound in Granville.

Visiting

Status
Open daily in daylight
Managed by
Ohio History Connection
Hours
The Octagon Earthworks is open daily during daylight hours, with staff at the visitor center during posted hours. The Great Circle has a museum; check hours.
Admission
Check with the Ohio History Connection.
Please note
Do not climb or walk on the walls.
Official information →Directions

Parks nearby

Buckeye Lake State Park
About 12 miles · Ohio's oldest state park, with a floating bog and a canal-feeder lake.
Open
Dillon State Park
About 20 miles · A lakeside park close to Flint Ridge and Blackhand Gorge.
Open

Details last checked 2026-09-22. Confirm hours and prices before you go.

Know a place that belongs here, or spotted something out of date? Email hello@fieldnotesohio.com.