This year, Americans can mark the centennial of the National Park Service with a commemorative coin or T-shirt or 16 new Forever stamps. Subaru, Airstream and REI are all eager to brand and bond with park-goers, a lucrative market that mounted to 307 million visitors in 2015. Like overweight, unruly guests, we strain at the belt of our national wilderness, popping newborn bison into our hatchbacks and tromping off the trails.

So it comes as a welcome surprise that the 60-year-old environmentalist Terry Tempest Williams could visit Big Bend National Park in Texas for 10 days in January 2015 and have it to herself. “I want to be absorbed into someplace larger and more expansive than the human brain,” she writes. “I am seeking a different kind of circuitry, the nervous system of rivers and deserts and mountains born of fire . . . If the world ends, let me be here.”

Readers who like their prose ardent and their politics leaning left will take particular pleasure in “The Hour of Land: A Personal Topography of America’s National Parks.” Best known for her contemplative memoir, “When Women Were Birds,” Williams has stitched together 12 strikingly different essays, each centered on a national park, battlefield, seashore or monument. Twenty-two black-and-white photos from artists such as Lee Friedlander, Sally Mann and Richard Avedon elevate these pages. Ken Burns taped an eloquent snippet with Williams for his PBS series on the parks.

She comes with some nifty bona fides. A lifelong hiker, she needed 136 stitches to close a gash to her forehead caused by a fall off a cliff in Utah. A Westerner whose father was nicknamed “Teton Tempest,” Williams writes an absorbing chapter on Grand Teton National Park and the gnarly politics of John D. Rockefeller Jr., who surreptitiously bought up the land to donate to the federal government.

Even better is Williams’ portrait of Valerie Naylor, superintendent of Theodore Roosevelt National Park in the North Dakota badlands. She gamely manages what is now “an island within a sea of oil development,” and has testified on behalf of oil companies when she’s struck a compromise worth defending. Naylor finds the heads of gas and oil companies easier to reason with than her state governor or legislators.

“Most of the issues confronting our national parks today are political,” Williams writes. “Should Devils Tower National Monument be respected as a scared site to Kiowa people or managed as a recreational site for climbers?”

advertisement | advertise on newsday

Right from the jump, Williams notes that American Indian “reservations were being established at the same time as national parks.” She exhibits her trademark sensitivity to those on the margins.

Williams writes plainly that she is no historian or scientist or public policy lawyer; she is a citizen activist. And “The Hour of Land” is a meandering read — best tackled as discrete chapters on different days. (Those seeking a crisper focus on the national parks should turn to David Quammen’s excellent, ongoing series for National Geographic magazine.) But Williams is frequently a lyrical writer and an intrepid thinker. She notes, for instance, that reintroducing condors in the Grand Canyon has helped park rangers locate the dead, cutting the search window by days in a place notorious for suicide.

The writer quotes the poet Rumi and the theologian Karen Armstrong, a prison menu from Alcatraz and the lyrics of Fela Kuti and Pussy Riot. She ends her fourth visit to Gettysburg with a re-enactor, Confederate flag on his bicep: “The best way for you to understand the Civil War is to look at the gun issue in America right now,” he says. “You ain’t taking my guns away. Slaves. Guns. It’s the same issue, just different items.”

Such racism would tempt me farther into the wilderness too. Instead, Williams douses her readers with sorrow, collected along the Gulf Coast island parks in the wake of the Deepwater Horizon oil spill.

Edward Abbey, the cranky environmentalist and misanthrope, haunts these pages — Williams reprints her long, posthumous letter to him. She also tucks in her letters to the Secretary of the Interior and the editors of the Los Angeles Times, Salt Lake Tribune and the Progressive. It takes a certain robust ego to place one’s readers at this after-the-fact, over-the shoulder remove. Collected sermons, anyone?

Still, Terry Tempest Williams’ ideas are worth wrangling. Reading her is better than buying a commemorative postage stamp — she delivers us into a more thoughtful grove.