The Trail of the Lonesome Pine (1936)

A feud, the origins of which can barely be remembered, has been boiling for decades between two sheltered mountain families, the Tollivers and the Falins. With plans to build a railroad through both families' land and mine coal deposits beneath it, enterprising outsider Jack Hale (Fred MacMurray) inadvertently becomes entangled in the region's politics. He soon captures the attention of the beautiful June Tolliver (Sylvia Sidney) and quickly becomes involved in a love triangle with her and her cousin Dave (Henry Fonda)