One way or another, all movies are road movies: what attracts us to the cinema is the chance to sit still and watch the world go by. So in Nomadland, when an ageing woman motivelessly quits her settled life, loads her truck with kitchenware, a bunk bed and a bucket for her bowel movements, then drives away through western America with no particular destination in mind, we are instinctively eager to accompany her.

But this is a road movie of a different kind. The narrative is no longer confidently exploratory or triumphantly imperial, as it was when John Ford followed pioneers across the prairies in westerns like Wagon Master or tracked the laying of rails for locomotives in The Iron Horse. Ironically enough, Nomadland begins in an actual Nevada town called Empire, emptied out when a gypsum mine closed ten years ago and caused the local zip code to be erased. This implosion provokes Fern, the deracinated widow played by Frances McDormand, to pack her belongings and head off through a series of equally wasted lands – tracts of barren Arizona sand, whittled ramparts of lunar rock in South Dakota, the fog-blurred coast of northern California, lashed by a cold, wild ocean. The wide screen has never looked bleaker, as the anamorphic lens here encompasses emptiness not infinitude. The film’s colour palette is chilly; the deserts are ragged; skies frown or glower; the occasional sunset resembles a haematoma. One of Fern’s chance acquaintances speaks of her own ‘healing journey’, but the itinerary is hardly therapeutic. The motto of these travellers, who arbitrarily coincide and then drift apart, is ‘See you down the road.’ They are not referring to a likely reunion at a diner somewhere ahead but anticipating their deaths, when before too long, at staggered intervals, the tarmac will run out.

Based on a non-fiction book by Jessica Bruder – a report on elderly dropouts unhoused by the crash of 2008 who took to the road in camper vans, periodically pausing to do casual work in Amazon warehouses or fast-food restaurants – Nomadland begins almost as a documentary. But the writer and director Chloé Zhao is not documenting an economic problem and its social consequences. Instead she quietly, absorbingly shows us Fern going about the business of living, doing the unremarkable things that occupy us all for most of the day. She opens tins of food and pensively chews the contents; she makes use of the aforementioned bucket after a sudden spasm; she goes on detours to predictably dreary laundromats. The force of suppressed emotion with which McDormand invests these actions is astonishing: the film’s small tragedy concerns a piece of broken crockery, and when she manages to repair it our relief is quite cathartic.

This stylistic rigour suggests the neorealism of Italian directors like Roberto Rossellini and Vittorio De Sica in the 1940s, though there are also wonderfully surreal episodes, in which Zhao, who was born in China but moved to Los Angeles as a teenager, acknowledges the strangeness or madness of her adopted country. Spectrally clad in a nightdress, Fern haunts the blanched, flimsy facades of a ghost town; in another nocturnal scene, she visits the Wall Drug dinosaur, a gigantic green brontosaurus with electric eyes installed beside the highway outside the Badlands National Park to advertise a shopping mall. Mostly, however, she just looks at the people she meets – three of whom are grizzled transients interviewed by Bruder for her book, here neorealistically cast as themselves – and listens with tender solicitude to their tales of woe.

Although Nomadland is set in 2011 and was made in 2018, it suits the frustrated, suspended condition of our present moment. Despite the mobile landscapes, it’s about physical enclosure, making do with less and the demanding vocation of solitude; Fern even gives herself a brutally spiky lockdown-style haircut. Perhaps inevitably, the film doesn’t quite have the courage of its downbeat open-endedness. A back story is eventually sketched in to explain Fern’s eccentricity, and there are manufactured entanglements with the relatives she rejected and another, cosier clan she is invited to join. As she nears California, her ascetic renunciation weakens and she revels in the glories of America the beautiful. She strips off to float baptismally in a mountain pool, her arms outstretched to embrace the sky, and in the redwood forest she hugs a sequoia. There is even a walk-on for a bison. McDormand, elsewhere indistinguishable from a supporting cast of amateurs recruited along the way, is allowed one discordantly actressy moment when she recites a Shakespeare sonnet to cheer up a depressed young vagrant, who resumes his trek with an iambic spring in his step. Back in Empire, she is also supposed to have coached a neighbour’s little girl to memorise Macbeth’s numb, despairing speech about ‘tomorrow and tomorrow and tomorrow’. The task matches the mood of Nomadland, but the anecdote feels implausible.

While life trundles by outside the window of the van, what makes Nomadland so touching is the life incised on McDormand’s sorrowfully long, ruefully funny face. The grand, humane gift of cinema has always been its close-up scrutiny of faces like hers, which we perceive as living organisms, not pictorial masks, somehow rendered transparent so that we can intuit unarticulated thoughts and share undeclared feelings. The movie’s entropic travelling turns out to be secondary; McDormand’s guarded but rawly sensitive countenance is a map of injured America and a motion picture in itself.