In the summer of 1936 near Austerlitz, New York, Millay was thrown from a moving station wagon when a door flew open, landing in a gully and sustaining severe injuries to her arm and back. This occurred at Steepletop farm and marked the beginning of long-term health struggles.

The chronic pain from the accident profoundly affected Millay's later life and work, contributing to themes of suffering, mortality, and resilience in her poetry from the mid-1930s onward. It led to increasing reliance on prescription morphine and alcohol, which complicated her creative process and personal relationships, yet she continued producing significant works like rewritten manuscripts. The experience deepened her empathetic engagement with human frailty and added layers of melancholy and defiance to her lyrical style, reflecting the physical and emotional toll of fame and independence.