In 1925 Marin created some of his most monumental and expressionistic landscapes, mature pivotal works in his oeuvre. In Sheldon Reich's estimate, the broadly painted forms, the textured, almost gestural brushstrokes, and the strong linear contours of watercolors such as Back of Bear Mountain "do not give up form of expression...[but] sublimate one for the other to achieve an expression carefully formed." Marin's interest in the underlying structure of his subjects is evident in its clear organization, calligraphic line, and large planes of pure, intense colors. The energy and warmth of the sun are evoked by the golden-yellow lines that radiate down from the hot sphere in the upper left.
Marin was seriously ill in 1925 and while recuperating made four weekend trips to visit his cousins, Lyda and Retta Currey, who were summering in the Berkshires in Massachusetts. It was during one of his trips north that Marin paused in the Hudson River Valley in New York to paint six watercolors, three in Haverstraw and three at Bear Mountain, including Back of Bear Mountain and Hudson River Near Bear Mountain, 1925.
When Marin exhibited these watercolors in December of the following year at the Intimate Gallery, they were well received by the critics, one of whom wrote that Marin "had nearly arrived at the expression he seeks" and that he was "more able to grasp his subject, analyze it and transpose its essence with added richness." Another wrote that his "exhibition...holds a challenge, a fulfillment and a promise." When Phillips visited the exhibition he was enthralled, later stating that he had "been drinking deep of their exhilerating [sic] beauty and vitality."