I like to walk in the American Revolution. It’s something I do a lot. You get some old maps and pick out a route—a retreat, a long march—and maybe convince a friend to come along, and then you are off into the past. New York is a great place for it anytime, but especially in the fall, especially when it starts to get cold. The Revolution was fought mostly around here, after all, and the angled streets indicate old routes everywhere. Lately, I’ve been remembering that my father, who passed away a couple of years ago, would point to hills and rivers and bridges when I was a kid, often referencing George Washington, who still feels to me like the guy who left the party just after I arrived—in my case, the party is the landscape of New York and New Jersey.

Walking the Revolution isn’t so much about the past, though naturally when you do it you try to imagine you are there. It’s really about seeing where you are now. I got a little more serious about it when I started to read a lot of accounts of what might be called gonzo exploring: climbing into old sewers looking for old streams, breaking into infrastructure. That all rubbed me the wrong way; it seemed too intentional, bringing more attention to the underground explorer than to the old stream. In contrast, walking in the Revolution is less about you, more about the land—call them soft reënactments.

I vary my walks. Once, I walked three days from the site of the Battle of Princeton to a small chain of mountains that New Yorkers generally have no idea is staring them in the face: the Watchungs. The Watchung Mountains are arguably the reason that Washington won the war, a place where he was in defensible striking distance of the British headquarters on Manhattan Island, a place with streams strong enough to run mills, with wood for fuel and shelter, with access to ore. Today, we know the Watchungs as part of the watershed-protecting Highlands that are crucial to the area’s ecological health: four and a half million people in New York and New Jersey get their drinking water from here. About ten years ago, I was researching a book when I realized that the points at which Washington posted lookouts in the Watchungs were all re-used, about a hundred and seventy years later, when the U.S. Army set up anti-aircraft batteries at those same sites to protect against Soviet bombers.

In 2012, I walked the route of the 1776 evacuation of Manhattan, from Fort Lee across the Meadowlands. I did not walk all the way to the other side of the Delaware, but stopped at the end of the day in Passaic, picking up a very famous walk that Robert Smithson, who was also interested in Washington’s routes, did in 1967: he wrote it up in an essay entitled “The Monuments of Passaic.” My walk from Manhattan to Passaic was a week or two after Hurricane Sandy hit the region, and the areas that had been used to hold back the British—swamps, tough-to-cross streams—were brought back to active duty by the storm; like the British, I had to be careful crossing some recently flooded bridges. I noticed that the oldest Dutch houses, as opposed to a lot of developments from the nineteen-eighties and nineties, were built on high ground. You could see, in other words, that we were once always ready for hurricane season, or that, to paraphrase the words on the flood maps of New York City’s Office of Emergency Management, we knew our zones.

As it happened, I got laid up after that walk, and had to put my walks on hold for a while. In that time, I missed walking. I missed that landscape-painter feeling, seeing the shape of the land, seeing its complement, the local watershed. Finally, last year around this time, I resurged and finally got around to walking a route I had long put off, a route that for a long time I had trouble visualizing: McGowan’s Pass, Washington’s retreat through a cut in the hills between lower Manhattan and what was then the village of Harlem, an approximately five-mile-long route, made late in the summer of 1776. ...