New Hampshire covers about 6 million acres and people were living and traveling all over it for at least 12,000 years before Europeans arrived.

But those pre-Contact people didn’t leave much evidence for us to see. The Granite State doesn’t have a stonehenge or huge burial mounds, or step pyramids, not even cave dwellings since our geology doesn’t have caves. So if you’re an archaeologist interested in how people lived here after the glaciers retreated around 14,000 years ago, you have to work hard to find your data.

To start off, where do you look?

“Basically, anywhere you would imagine would be nice to camp. Places that are not rocky, are level, have resources, food – wetlands are good,” said Gemma-Jayne Hudgell, a principal investigator for Northeast Archeology Research Center in Farmington, Maine, who has been analyzing a couple of sites in the town of Dummer, north of Berlin.

Hudgell will be talking about that work at the annual meeting of the New Hampshire Archaeological Society on Saturday, Oct. 19, at StrawberyBanke Museum in Portsmouth, which is why I contacted her. I was curious not just about what happens at an archaeological dig, which is always interesting, but how they figure out where to dig.

That rule of thumb about good camping sites is trickier than it sounds. Over thousands of years, rivers shift, ponds disappear, erosion fills in gullies and creates new ones, the climate changes. “You have to think about not just what the landscape is today, but what it would have looked like back then,” Hudgell said.

For example, an obvious spot to look for settlements is next to rapids on major rivers where fish congregate. A good example is Amoskeag Falls in Manchester, which was a huge gathering place for Native Americans.

But Hudgell surprised me: Sites like that are fine for more recent sites but not for evidence of people who arrived soon after glaciers left.

“Sites along rivers, they don’t start to come in until a couple thousand years later,” she said. “The landscape needed to stabilize along rivers before people would be there” long enough to leave a trace we can find.”

Which leads to another question: what is left to trace? Organic material like cloth, wood tools, tent poles and fishing gear is long gone, and so are human remains. Our soil is generally so acidic that bones don’t last thousands of years. (If archaeologists do find human bones, the police get called in.)

This lack of evidence “is one of the reasons people say there were no Indians here,” said Hudgell.

She told me that archaeology and anthropology in New Hampshire can thank the passage of the National Historic Preservation Act of 1966, which requires archaeological surveys to precede many public road and development projects. A large majority of pre-Contact findings in New Hampshire have occurred in the past half-century, discovered while surveying an area before the excavators tear it up.

That includes Hudgell’s work in Dummer. Her firm was called in by the state Department of Transportation in advance of upgrades of Route 16 along the Androscoggin River. She found two small sites – “about the size of a room” each.

So how can she tell that nomadic people stayed in a certain location for a week or a month some 10,000 years ago?

One obvious thing to look for is ceramics. But, Hudgell said, really early settlements had little or no pottery. Instead, she looks for small bits of stone that have been shaped to serve a purpose.

“What we find most commonly is the waste. Flakes, chips, projectile points, tools, simple knives, little weights for fishing,” she said.

“We often find rocks used for cooking. They were put around the hearth and heated, then put into water to warm it up.” That’s a trick which societies need when they don’t have pots that can be placed onto the fire.

Those rocks, it turns out, crack from the heat in distinct ways. If you find some of them, it’s probably part of a discard pile near a firepit built for the days or weeks that a fishing or hunting party was in the area.

Once discovered, a hearth area itself can be full of information. Sediment tells what they were eating – seeds of plants, or bones of fish or animals. Those bones can survive the acidic soil because of chemical changes due to cooking, and are usually the source of radio-carbon dating that tells archaeologists whether they’re looking at something 3,000 years or old or 13,000.

The ground itself can also hold clues, interestingly. People disturb the ground where they live, and that disturbance can be reflected in the color, density and other aspects of layers of underground soil. If you know what to look for, of course.

Admittedly, this won’t help you and me see evidence of the state’s earliest inhabitants. But it does raise an interesting thought: Whenever we wander near a stream or river, there’s a chance that we’re strolling where people strolled when wooly mammoths were still around.

If that doesn’t boggle your mind, nothing will!