There are six notable islands in the Hudson River below Albany, from an unnamed islet north of Saugerties to Rattlesnake Island off of Coxsackie.

Accessible only by small boat in the summer, and completely inaccessible in the winter, these islands have dodged civilization – though there are houses, industrial plants, even small cities on either shore, the islands are cut off from modernity, and exist outside of time. Walk a few strides into one, close your eyes, and open them. Are you in the same epoch? Are the cities still there?

This is different than saying humans have never touched the islands – they have, but the interactions have been of the unsanctioned, anarchic sort. Cabins have been constructed, then burned; ships have run aground; hermits have taken up residence; and riotous bacchanalias have been held in the night.

Here are the three main islands.

Stockport Middle Grounds

I first paddled to this seemingly vacant island because it was obvious someone was using power tools on it.

Located perhaps a half-mile from the wildlife explosions of the Stockport Creek delta, about five miles north of the City of Hudson, the island is about 4,000 feet long, its western shore made of sandy beach, it’s eastern shore a brake of green arrow arum.

After lugging my kayak above the high tide line, I came upon the source of the noise I had heard from the shore: someone had cleared a small area of brush, setting up a few chairs, a grill, and a fire pit. A boom box was cradled in the joint of a tree, and a sign whittled out of a board was nailed above the campsite reading: Caveman’s Island.

The cavemen were not there. It was early morning on Labor Day weekend, about 7 a.m., and I ambled along the rim of the island, its sandy beach exposed only during the river’s low tide.

I came upon a multigenerational band bivouacking in the same clearing they had come to every Labor Day weekend for the last 20 years. A young teen was monitoring the progress of two adults picking their way through a maze he had drawn in the sand, while a toddler and his father hunted for caterpillars.

I sat and chatted with the group for a good half hour – on the islands, any social reticence dissolves, because we’re all in this together.

The interior of Stockport Middle Ground is easier to penetrate than the other two islands. Walking from the island’s southern tip reveals a panoply of vegetation, markedly different and more varied than the flora of the Catskills – silver maple, green ash, sycamore and Kentucky coffeetree spread above, while bindleweed stretches from the tree’s low boughs.

Various beer containers – pull-tab cans, plastic 40s, glass quart bottles – are scattered on the forest floor, decades of drinking detritus, all their labels corroded away with time.

Walk about 100 feet into the forest and you’ll come to a ten-foot earthen embankment, the edge of a short plateau covering most of the island.

Middle Ground Flats

Middle Ground Flats sits between the city of Hudson and the town of Athens. I became interested in the flats a few months after moving to Hudson when I saw a full Wiffleball game being played on the flats’ broad, sandy shore when the tide was out.

There’s a long relationship between Hudson and the flats, which stretch up the river for about a mile and a half. The city’s namesake, Henry Hudson, supposedly ran aground here while sailing the Half Moon up the river while exploring the region.

Though there was a long sandbar off Hudson since before the city was founded in the 1780s, the flats are partially artificial, built up with earth dredged from the river bottom to maintain a shipping channel.

The Rivers and Harbors Act of 1910 authorized the U.S. Army Corps of Engineers to maintain a 12-foot channel between New York City and Albany, a depth increased to 27 feet in 1925 and 32 feet in 1954. The stretch of the Hudson River from just south of the Middle Ground Flats to Albany was dredged during this time, and completely changed the river from its natural state. This stretch used to be a twisting cord of side-channels and marshland, instead of the single channel it is today.

The dredged earth dumped on the sandbar allowed trees to grow on the Middle Ground Flats, first on the island’s rim. The center of the island remained bare from trees until the 1960s.

The first known cabins were built on the island’s northern tip in the early 1900s, an island version of Hudson’s shantytown. The cabin’s fabricators never owned the land the cabins sat on, or had any sort of permission to build them, but they did so anyway, because who was going to harass them all the way out there anyway?

The cabins, numbering more than a dozen, burned to the ground in the 1980s. One of the downsides of owning an unsanctioned cabin on an uninhabited island is no one comes running when it starts to smoke.

I kayaked around the whole of Middle Ground Flats this summer, and new cabins have popped up on the Hudson side of the island. They were constructed by some of the families who built the original cabins in the 20th century, according to local historian Leo Bower. There they sit, un-harrassed, thumbing their noses at the city on the opposite shore, where housing is hard to find, and you certainly have to pay for it.

Roger’s Island

You can see Roger’s Island while driving over the Rip Van Winkle Bridge just south of Hudson, but it can be mistaken for a large brake of aquatic plants.

Which is not to say it’s small – it’s about a mile tip-to-tip – but that it sits low in the water, the river almost flowing through the island at high tide, reducing some of the surface area to individual humps of earth surrounded by water.

The island’s southern shore is split by an inlet stretching halfway through the island’s length. Kayaking through the inlet brings you under the span of the Rip Van Winkle Bridge, the monolithic iron piers rising out of the marshland like the legs of some giant automaton, some metal Titan who has never looked down.

Along the shores of this inlet are various sub-inlets, aquatic passageways that split and split again, creating a maze of channels to kayak down. Round any bend and you’ll come upon a new scene – a great blue heron emitting its bass croak, a flurry of wood ducks flapping into flight, a fish surfacing – just don’t get lost.

The best way to see all three islands is on a kayak, but the Hudson River’s tidalites can make a half hour trek downstream into an hour-plus trek on the way back.

But it doesn’t matter so much. Because there is no time when you’re on the river.