"Wild" is based on a New York Times best-selling memoir that chronicles Cheryl Strayed’s (Resse Witherspoon) 1,100-mile hike up the Pacific Crest Trail. (Fox Searchlight)

In “Wild,” the stirring adaptation of Cheryl Strayed’s 2012 memoir, Reese Witherspoon delivers an admirably restrained, un-glamorous performance as the author, who at age 26 hiked 1,110 miles of the Pacific Crest Trail from California to Oregon in a ritual of physical endurance, philosophical reflection and spiritual cleansing. Grieving the loss of her adored mother, guilt-ridden by the dissolution of her marriage and the indiscretions that preceded it, Strayed sets out impulsively and alone, her brand-new equipment so heavy that she can’t even stand under its bright, shiny, utterly impractical weight.

She loses some of the gear but still carries enough emotional baggage to keep her overburdened throughout a journey that will take her through the searing Mojave Desert to a freak snowstorm and finally the crags and ranges of the Pacific Northwest. Along the way, the particulars of Strayed’s life — her fraught relationship with her mother (played with radiant spontaneity by Laura Dern), her heroin use and extramarital affairs — come into focus by way of jagged flashbacks. These visions, while eloquent, are brief, as Strayed is continually pulled back to the present by the realities of the road or encounters with fellow travelers. Relying on the kindness of strangers, Strayed seems to reenter the world even as she trudges along on a fruitless quest to leave it behind.

At first glance, “Wild” invites some obvious comparisons to other movies about reckless risk and solitary treks — Sean Penn’s masterful “Into the Wild,” Emilio Estevez’s “The Way,” about the Camino de Santiago, and this year’s “Tracks,” in which Mia Wasikowska starred as a figure similar to Strayed, a woman walking across Australia to exorcise her demons. Thankfully, screenwriter Nick Hornby and director Jean-Marc Vallée (“Dallas Buyers Club”) have brought their virtuosity to bear on a narrative that unfolds episodically — literally one step at a time — but also poetically. With an evocatively layered sound design and those shardlike flashbacks, Vallée especially succeeds in creating a convincing inner life for a woman who remains something of a cipher even at the film’s most confessional moments.

Those usually have to do with Strayed’s mother, here portrayed as a warm, nurturing spirit who continually sacrificed her own intellectual and creative ambitions to care for Strayed and her brother. At one point, both women are attending college at the same time, and Strayed says something condescending about her mother’s reading Adrienne Rich in a women’s studies class; the memory stings, and there’s hardly a grown daughter alive who won’t be able to relate to her enduring shame and chagrin.

“Wild” is so well made, so beyond reproach narratively and aesthetically, that it’s difficult to say why it makes so little impact. While most viewers will be dutifully affected by Strayed’s journey, many may find themselves curiously unmoved.

One problem may be that “Wild” is too interior to benefit from a literal reenacting. Another may be the film’s greatest asset, which is Witherspoon herself. As with the wonderful drama “The Good Lie,” “Wild” is a project she brought to the screen as a producer, her presence in the film no doubt guaranteeing that it would get made. As admirable as that is and as bravely as Witherspoon dresses down to play the glum, emotionally distant Strayed, there’s not a moment in the film when we can forget that we’re watching Reese Witherspoon.

Or maybe the problem is that this Reese Witherspoon isn’t the one we like to watch. It’s understandable that, after winning an Academy Award in 2006 for her dramatic turn in “Walk the Line,” she would want to test her limits outside the confines of the comedies that made her famous in the 1990s. But can anyone argue that she’s never been better than as Tracy Flick in “Election”? Did anyone else see Witherspoon’s producer credit on “Gone Girl” and imagine what she might have done with the similarly satirically rich Amy Dunne? There’s no doubt that Witherspoon has smarts, taste and superb instincts, but they’re wasted on Strayed, who, despite the sincerity of her self-reckoning and the physical courage of her journey, remains a strangely obscured figure in her own story. “Wild” is an accomplished movie, and often a beautiful and moving one, but the woman at its center remains warily at arm’s length.

★ ★ ½

R. At area theaters. Contains sexual content, nudity, drug use and profanity. 115 minutes.