"So we're going to walk nine miles?" our oldest daughter asked.

"No," I said, "only eight."

"Why didn't we train for this?"

"It's not that far."

Actually, the Grand Portage, a trail at the eastern tip of Minnesota's arrowhead, was closer to 8½ miles. By the end of the day, we'd feel every step of it, as travelers had for the past 2,000 years, hauling their canoes and goods between Lake Superior and the Pigeon River.

There was no turning back. This was a trip we'd planned long ago. Besides, it wasn't impossibly far, but it was impossibly cool: the idea that we'd walk the same path used by Anishinaabe and Cree travelers, French-Canadian fur traders, and British soldiers. We'd be traveling back in time on a true "por-taage," as the voyageurs pronounced it in French. It means a "carrying," and in this case, it would be a "big carrying."

The four of us—me, my wife, and our daughters—had gotten our National Park Service backcountry passes to camp for two nights on the Pigeon River at the site where Fort Charlotte used to stand in the late 1700s. Our daughters, ages 10 and 12, accepted the plan when we'd made it. Now they were having second thoughts.

"Don't worry," I said. "You'll be fine."

In fact, I didn't know how long it would take, or how hard it would be. We'd camped many times, but never backpacked. All I knew was that we should be able to make it in a day. After all, the voyageurs carried 90-pound packs of beaver pelts on the Grand Portage—sometimes two at a time. We weren't carrying that much, although my pack did feel a little voyageuresque.

Packs loaded, we drove to the trailhead on Lake Superior at Grand Portage National Monument, the Park Service historical site that manages and maintains the trail. Next to a wooden sign marking the trail's start, we hoisted our bags onto our shoulders, took a look back over the great lake, then headed into the past.

The path was wide enough for one person, and it climbed quickly at first, but not too steeply. The portage cuts through a gap in the hills known as the Grand Portage Highlands. Today the trail, managed by the National Park Service, runs straight through the Grand Portage Indian Reservation.

After about a mile, not long after we crossed Minnesota State Highway 61, we met a group of boys from a Wisconsin camp. They were taking turns portaging canoes at the tail end of a six-day canoe trip down the Pigeon River, and they were elated to hear they had only a mile left.

We didn't. For us, the Old Highway 61 was still another three miles ahead, and our camp was another seven or so. (You can actually park at the old 61 crossing for the day with a permit from headquarters if you want a quicker hike.) Still fresh, we marched on, moving fast through the quiet boreal forest. Parts of the well-maintained path were covered by boardwalks; others were muddy. We saw fresh tracks from moose and wolf, but encountered no other people.

After cresting the initial rise, the trail rose and fell. It crossed small creeks, then came to a road on Abita Ridge that marked the halfway point—aabitawikana in Ojibwe.

It had rained recently, and the boardwalks were slippery. Both girls slipped and fell. Neither was badly hurt, but it was the beginning of a decline in morale. After about four hours and as many miles, we were tired and hot. When we arrived at a swamp—the voyageurs waded through; we crossed on a boardwalk—we figured we were at about five miles.

"How are we going to do this?" asked our oldest, sounding a little panicked.

"We just keep going," I said. "There's only a 5k left."

That seemed to help. She had run a 5k race and could wrap her mind around the distance. But the relief didn't last very long in the heat.

"Do you think we're almost there?" she soon asked.

"Just don't think about it," I said.

She was silent for several minutes before saying, "If it's not around the next corner, I'm stopping!"

We came to the next corner, and it was not there. But she kept walking. She said the same thing a few more times before she actually stopped, and my wife waited with her until she could pick herself up again.

Finally, after walking for more than six hours, we came to the riverside campsite. We threw down our packs and lay on the tent platforms staring at the sky. Our legs ached. Our backs hurt. I had bruises on my hips from my pack. We lay there for a long time until it started getting dark. A light rain began to fall, and we roused ourselves to set up camp and eat dinner.

We all slept hard. The next morning it was still raining, so the girls played in the tent and my wife read. I put on my rain jacket and went down to the river. It was strange that this was the edge of Minnesota, the edge of America, and that the other shore was another country.

"Canada looks like the United States," said our oldest daughter when she came down to join me. Cedar waxwings darted out from trees on the shore. The sound of the water running over rocks was a balm.

Back at the campsite, we heard a thump and turned to see a fisher running through the trees. We had no cell phones, no link to the outside world. It felt like we were in a time capsule, as if a birchbark canoe could come around the bend at any moment.

The sky grew dark. The rain returned. I watched the campfire embers sputter under the drops, and thought of the countless fires that had burned here.

The next morning we made breakfast, packed our bags, and steeled ourselves for the trek home.

"Should be easier this time," I said. "We know the landmarks."

We were rested and in good spirits. We felt stronger. We moved faster. The trail wound through the forest, and soon we came to the swamp.

"That seemed really fast!" our youngest said.

We kept up a good pace, and soon the trail started down toward the lake. We were cruising until we came to another rain-slicked boardwalk where I slipped and fell forward, helpless to stop the momentum of my massive pack. In slow motion it pushed me down. With trekking poles in my hands, I could see the wood approaching my face, but all I could do was tilt my head down to avoid breaking my nose. My forehead bore the brunt of the blow. I lay unmoving for several seconds.

"Are you OK, Daddy?" our youngest daughter asked.

"I think so," I said, struggling to my feet. Each family member cringed at the lump protruding from my head.

But we had to go on. Downhill toward the big lake we went, and we were practically running by the time we reached the trailhead, where the wide waters of Lake Superior opened before us. We stood there for a minute, then dropped our packs and lay in the grass, happy to reach the end of our grand portage.