The story of American immigration is fundamentally a story about sky—trading the endless horizons of rural homelands for narrow urban canyons and industrial smoke. Between the 1840s and 1920s, five families made profound journeys from Europe’s most open landscapes to America’s most crowded neighborhoods and industrial centers. From County Kerry’s rolling plains to the High Tatras mountains, from Swedish forests to Polish farmlands, these immigrants left behind unlimited skies that had defined their daily experience. What they found in Brooklyn’s tenements and Johnstown’s steel mills was a world where Jacob Riis observed that “that strip of smoke-colored sky up there is the heaven of these people.” This is the story of environmental displacement—trading seasonal rhythms for industrial time clocks, scattered rural communities for the most densely populated urban neighborhoods and hazardous factory towns in American history.