After the 1943 closing of Stites Hospital, the Mercer County Board voted to construct a new hospital, which opened February 1, 1950. Generous financial donations were given to the hospital that began a tradition of Mercer County residents supporting their facility.
- Mrs. Harriet Batson Hayden of Pasadena, California established a trust giving 415 acres of prime farmland to the hospital.
- George Huffman willed $50,000 as a hospital trust fund.
- Elisha L. Essley, owner of the Essley Tool Company of Chicago, who in 1950 contributed $15,000 to the hospital, funded the surgical suite.
- Olive Lant, Beatrice Leona Bopp, Ludwig Samuelson, and Clarence L. Anderson also donated substantial funds to financially strengthen the hospital.
By the late 1950's, the hospital was operating at maximum capacity. Many times there more patients than available beds. In 1972 new state licensing requirements had to be met in order to meet the Life Safety Codes and participate in the Medicare Program. The hospital would need to make several improvements in order to meet the new requirements.
Mercer County Board realized the need for a new facility and voted in 1980 to build a new hospital. Construction began July 1, 1980; a Grand Opening and Dedication Ceremony were held on February 26, 1981.
The hospital planned a $10.5 million renovation in the first decade of the new century. Renovation plans included a new mechanical system, expanded Laboratory and Physical Therapy services, and conversion to single patient rooms to provide privacy and safety. Mercer Foundation for Health wanted to help in the renovation effort and conducted a successful $1 million campaign in 2008.
On February 1, 2013 Mercer County Hospital and Nursing Home became part of Genesis Health System. Mercer County Hospital was named Genesis Medical Center, Aledo and the Nursing Home was rebranded as Genesis Senior Living, Aledo. Medical Associates Clinic became Genesis Health Group, Aledo.