Stonehenge was built in stages over roughly 500 years, beginning as a simple circular earthwork around 3000 BC and evolving into the iconic stone monument around 2500 BC. No single generation constructed it. The project required sourcing massive stones from locations across Britain, transporting them tens or even hundreds of kilometers, and assembling them using engineering techniques borrowed from woodworking. The story of how it came together involves geology, migration, and a level of organization that still surprises researchers.
Phase 1: The Earthwork Circle
The first version of Stonehenge looked nothing like what you see today. Around 3000 BC, builders dug a circular ditch with an inner and outer bank, enclosing an area about 100 meters across with two entrances. This was an early type of henge monument, a ceremonial enclosure common across Neolithic Britain. Inside the bank, a ring of 56 pits (known as the Aubrey Holes) held timber posts or small standing stones and later served as burial sites for cremated human remains.
The site’s location wasn’t random. Naturally occurring ridges in the chalk bedrock, formed by deep periglacial fissures from the last ice age, happen to align with the midwinter sunset and midsummer sunrise axis. These natural lines in the landscape may have drawn early peoples to the spot long before anyone placed a stone there.
Where the Stones Came From
Two main types of stone make up Stonehenge: the large sarsens and the smaller bluestones. They came from very different places.
The sarsens, some reaching 9 meters long and weighing up to 50 tons, were sourced from West Woods in Wiltshire, about 25 kilometers north of the monument. A 2020 study published in Science Advances pinpointed this location by matching the geochemistry of a core sample drilled from one of the uprights to rocks in the West Woods area. For decades, researchers had been looking for the sarsen quarries a few kilometers further north, so the actual source turned out to be slightly closer to Stonehenge than anyone expected.
The bluestones are smaller (up to about 4 tons) but traveled a far greater distance. They originated in the Preseli Hills of west Wales, roughly 240 kilometers away. Excavations at two quarry sites there, Carn Goedog (spotted dolerite) and Craig Rhos-y-felin (rhyolite), suggest the stones were quarried between roughly 3400 and 3000 BC. The approximately 44 bluestones at Stonehenge include several rock types: spotted dolerite, unspotted dolerite, rhyolite, and other volcanic stones. This variety suggests the builders drew from multiple quarry locations across the Preseli ridge, possibly dismantling one or more existing Welsh stone circles to supply the project.
The most dramatic origin story belongs to the Altar Stone, a shaped 6-ton sandstone block that sits at the heart of the monument. Long assumed to be Welsh, a 2024 study in Nature revealed it actually matches rock from the Orcadian Basin in northeast Scotland, at least 750 kilometers from Stonehenge. How a block that size traveled from Scotland to Salisbury Plain remains an open question, but it points to connections across Neolithic Britain that were far more extensive than previously imagined.
Moving Multi-Ton Stones Without Wheels
Neolithic Britain had no wheels, no metal tools, and no draft animals capable of hauling 50-ton blocks. The exact transport methods remain debated, but the leading theories involve a combination of wooden sledges, rollers, and organized human labor. Experimental archaeology projects have shown that teams of a few hundred people can move sarsen-sized stones on greased wooden tracks, though no one has replicated the full 25-kilometer journey.
For the Welsh bluestones, water transport is a strong possibility. Some researchers propose the stones were rafted along the coast and up rivers, while others argue they were dragged overland the entire way. A now-largely-dismissed theory suggested glaciers carried the bluestones to Salisbury Plain naturally during the ice ages, but geological analysis has found no evidence of glacial deposits in the right locations to support this idea.
The Scottish origin of the Altar Stone adds another puzzle. A 750-kilometer journey by land would be extraordinarily difficult for a 6-ton block, making coastal sea transport the more plausible route, though direct evidence for Neolithic seafaring on that scale is slim.
Phase 2: Raising the Stones
Around 2500 BC, the monument transformed from an earthen enclosure into the stone structure we recognize. The sarsens were erected in two arrangements: an outer circle of 30 uprights capped with a continuous ring of horizontal lintels, and an inner horseshoe of five massive trilithons (pairs of uprights topped by a single lintel). The bluestones were set up between these sarsen formations in a double arc.
Getting the uprights vertical likely involved digging a hole with one sloped side, sliding the base of the stone into the pit, then levering and pulling the stone upright using ropes and timber frameworks. The holes have been excavated and show a characteristic ramp shape consistent with this technique.
Placing the lintels on top was a separate engineering challenge. The most commonly proposed method is a timber crib: builders stacked alternating layers of logs on either side of the uprights, raising the lintel a little at a time until it reached the correct height, then slid it into position.
Joints Borrowed From Woodworking
What makes Stonehenge structurally unusual for a stone monument is the joinery. The builders carved protruding knobs (tenons) on top of the uprights and matching hollows (mortise holes) in the undersides of the lintels, locking them together. The lintels in the outer circle were also connected to each other using tongue and groove joints, where a ridge on one lintel fits into a channel on the next. These are techniques normally found in carpentry, not masonry. The builders were applying woodworking knowledge to stone on an unprecedented scale.
Who Built It
Stonehenge was not built by a single community. Isotopic analysis of cremated remains found in the Aubrey Holes reveals that some of the people buried at Stonehenge during its earliest phase came from the Preseli Mountains in Wales, the same region the bluestones were quarried from. These individuals didn’t just supply the stones. They migrated with them and were buried at the site.
There’s also growing evidence that the bluestones may have first stood in a circle at Waun Mawn in the Preseli Hills before being dismantled and relocated to Salisbury Plain. Excavations at Waun Mawn uncovered empty stoneholes arranged in a circle roughly the same diameter as the ditch at Stonehenge, with four surviving stones of unspotted dolerite still in place. One of the empty holes even matches the unusual pentagonal cross-section of a specific bluestone now standing at Stonehenge. If this theory holds, the monument was partly a transplanted Welsh stone circle, carried south by migrating communities around 3000 BC.
Why the Building Took Centuries
The roughly 500-year gap between the first earthwork (3000 BC) and the sarsen stone phase (2500 BC) reflects a monument that was repeatedly reimagined. Each generation inherited the site and reshaped it. The bluestones were rearranged at least twice. The Aubrey Holes may have originally held timber posts before stones replaced them. The surrounding landscape also evolved alongside the monument, with a ceremonial avenue, burial mounds, and smaller stone settings added over the following centuries.
The sheer labor involved explains the extended timeline. Estimates suggest shaping and transporting the sarsens alone required millions of hours of work. Stone was pounded into shape using hammer stones (sarsen is too hard for chiseling with Neolithic tools), with each upright carefully dressed to taper slightly toward the top, creating an optical illusion that makes the stones appear straight-sided when viewed from the ground. That level of deliberate craftsmanship, applied to stones weighing up to 50 tons, represents a commitment of resources and planning that rivaled anything else happening in Neolithic Europe.