The High Divide by Lin Enger
In 1886, Gretta Pope wakes one morning to discover that her husband is gone. Ulysses Pope has left his family behind on the far edge of Minnesota's western prairie with only the briefest of notes and no explanation for why he left or where he's headed. It doesn't take long for Gretta's young sons, Eli and Danny, to set off after him, following the scant clues they can find, jumping trains to get where they need to go, and ending up in the rugged badlands of Montana.
Gretta has no choice but to search for her sons and her husband, leading her to the doorstep of a woman who seems intent on making Ulysses her own. Meanwhile, the boys find that the closer they come to Ulysses' trail, the greater the perils that confront them, until each is faced with a choice about whom he will defend, and who he will become.
Used hardcover in dust jacket, minor wear, remainder mark on bottom text block, binding tight, pages bright, a very nice copy!