Horizon is pleased to announce we are NOW HIRING Registered Nurses as full-time Professional Staff Nurses! About Horizon: Horizon - Shenango Valley: Located in Farrell, Pa., a city in the Shenango Valley area of Mercer County. The 54-bed hospital offers a variety of inpatient and outpatient services including general surgery, emergency services, orthopedic care, wound services, and oncology through the Hillman Cancer Center.