Most of those old walls are collapsed now, half-buried under leaf litter, swallowed up by second-growth forest. But they're still there — and the tradition of building them is still alive in New Hampshire, if you know where to look.
A UConn geologist named Robert Thorson made the estimate that New Hampshire alone once had close to 250,000 miles of stone wall. More miles of wall than road. Most were built between the 1770s and the 1820s, back when the state was almost entirely cleared farmland and the only way to get a field out of the woods was to pick the rocks up and set them somewhere you didn't need them.
I find that history hard to ignore when I'm building a wall today. Every one I put on a client's property is part of a tradition older than the state itself.
The difference between a wall and a pile of stones
Walls built in 1800 were mostly what a mason would call “dumped” — farmers throwing field stone onto a line between properties, getting the rocks out of the way as quickly as possible. Those walls aren't engineered. They don't have to be. They're there to mark a boundary or keep a few sheep in.
A laid wall is something different. Someone sat with every stone, turned it in their hands, chose a face, set it where it belongs. You can feel the difference standing next to one. A laid wall looks like it grew there.
The rule most wall builders follow — whether they know the phrase or not — is “one over two, two over one.” Every stone bridges the joint between the two below it, so no vertical seam runs more than a course high. That's what makes the wall behave like a single thing instead of a stack of individual rocks. A wall that isn't built that way will come apart in a decade. A wall that is can stand for two hundred years.
Dry-stacked vs. mortared
I prefer dry-stacked walls for most of the work I do in New Hampshire, and there's a reason that has nothing to do with aesthetics.
“The ground here freezes down close to four feet deep in a hard winter. A mortared wall is rigid — it can't absorb that movement. A dry-stacked wall moves with the frost.”
When the ground freezes, it expands. When it thaws, it shifts. A mortared wall can't give — so the joints crack and water finds its way in. Over ten or fifteen years the wall starts failing at every seam.
A dry-stacked wall settles and reseats every spring. If one stone slips, you pick it up and put it back. It isn't glued to anything. Most of the 18th-century walls still standing in New Hampshire are dry-stacked. Most of the ones that have fallen were mortared somewhere along the way.
There's a place for mortar — tight architectural features, sitting walls around a fire pit, veneer work over a concrete core. But for a property line, a retaining wall, or a free-standing feature wall, dry stack is almost always the right call.
What goes under the wall matters more than what's on top
The biggest mistake I see on homeowner walls — and on a lot of contractor walls — is no proper footing. A wall built directly on topsoil will move every year and eventually lean or bulge out.
The right base is simple:
- Dig below the frost line, or as far as practical for the wall's height
- Pack in a bed of crushed stone six to twelve inches deep
- Set your first course on top of that compacted base
- For retaining walls, add a perforated drain tile at the back, buried in crushed stone
Without that drainage, you've built a dam — and dams made of loose fieldstone don't last long.
The other piece nobody talks about is batter. A good retaining wall leans back into the slope about an inch of rise for every foot of height. That slight lean keeps the weight of the wall — and the soil behind it — bearing down and in, not tipping forward.
Choosing stones
On most of my jobs the stones come off the property. There's a lot of rock in New Hampshire — if you dig a hole for a foundation around here, you'll find enough for a decent wall. Native granite, fieldstone, the occasional piece of schist. I'd rather work with what's there than truck in material that looks out of place.
When I'm picking stones I'm looking for one thing above all: at least one good face and one flat side. The face is what you see. The flat side is what sits on the course below. You can work around the rest.
Big stones at the base. Smaller stones higher up. Long “through” stones every few feet that run the full width of the wall and tie the two faces together — those are what hold the whole thing in place.
Why people still build them
A stone wall changes a property. There's no way around that. It grounds the landscape. It says the land has been cared for. A raised bed edged in native stone, a retaining wall that holds back a driveway cut, a free-standing wall that defines a back lawn — these are the features that make a piece of New Hampshire land feel finished.
And unlike a deck or a fence, a properly-built stone wall is the last one you'll build on that spot. I've worked on walls that were put up before the Civil War. They still stand. They still look right. I don't think you can say that about much else.