The incident happened in the early hours of the new year. She has multiple serious injuries including a fractured spine and broken pelvis.
A spokesperson for North Yorkshire Police said:
Police were called to reports of a woman who had sustained injuries consistent with a fall at an address in Parliament Street, Harrogate at around 4am yesterday.
She was taken to hospital by ambulance. Her condition was described as serious but not believed to be life-threatening.
The full circumstances are to be determined as part of the investigation into the incident.