Imagine a book combining the best of James Michener and Tom Robbins, and a soupçon of several Jonathans: Franzen, Lethem, Safran Foer. Do you think "unholy mishegoss," or "intriguing patchwork"?

If you chose the latter, you'll love "West of Here," the sprawling new novel from Jonathan Evison ("All About Lulu"). The Michener part comes from the cultural and geographical exploration of Washington state's Olympic Peninsula, onto which Evison has grafted his fictional pioneer burg of Port Bonita; the Robbins part comes from the hapless, po-faced cast of eerily congruent counterparts set over a century apart in 1889 and 2006.

And those Jonathans? Combine the non-earnest bits of conservation talk from "Freedom," the layered community of "Motherless Brooklyn," and the skid toward oblivion in "Everything Is Illuminated," and you've got some idea of how Evison weaves his homespun: warm, textured and unfinished. In the end, the lack of resolution on several subplots frustrates a bit, but Evison's odd genius is to structure his novel geographically, its jagged edges and swirling storylines a mirror of the toothy mountains and uneven estuaries of its setting.

In 1889, Ethan Thornburgh arrives in the Northwest Territory seeking his pregnant lover, Eva Lambert, whose brother Jacob is also trying to coax the feisty would-be journalist back home to Chicago. Meanwhile, American Indian single mother Hoko and her half-white, perhaps half-witted, son Thomas Jefferson King negotiate life during a transition for their Klallam tribe as a dogged explorer named Mather leads an unfit band on a tale-chasing expedition through the Olympics in search of the Elwha River's source.

Their modern doppelgangers include single mother Rita, a Port Bonita barmaid whose son Curtis is as lost in modern life as Thomas Jefferson King once got in the Ho Rain Forest; an ex-con named Tillman who attempts to stake a misguided and underresourced claim on what's left of the Northwest wilderness and his meddling parole officer, Franklin; as well as Sasquatch hunter Krigstadt and his boss Jared, the modern scion of the Thornburgh clan, whom we learn, through various bits and pieces, managed to construct a dam with results as calamitous for the environment as beneficial for the family coffers.

Just as Thomas Jefferson King is content to sit for hours in one spot, Evison is content to leave his characters in medias res. We learn where a few of them go when they leave -- Eva returns to Chicago, for example -- but we never learn all about the connections between now and then or about what will happen to the ecological balance of the Elwha. The story, like the river, keeps flowing, its author showing us that there are some frontiers humans can never fully tame.

Bethanne Patrick is a critic and author who tweets as @TheBookMaven. She lives in Arlington, Va.