According to state corrections officials, Robin Staehr entered the public lobby at the women's prison around 5:15 p.m. on Sunday with a rifle behind her back, demanding to be allowed into the facility. Staff recognized Staehr as an employee who resigned from the facility in 2005.
Staehr was denied access to the facility and staff called 911 and immediately began to lock down the building and grounds.
Authorities say she then fired a single gunshot to her chin before dropping the .22 caliber rifle and walking to the parking lot.
Emergency responders transported Staehr to York General Hospital, after which she was transferred to a Lincoln hospital.
The incident is being investigated by the Nebraska State Patrol.
No staff or inmates were injured during the incident.