at age 98, johnston moved from iowa to ohio in order to live with her daughter and son-in-law. even after turning 110, she continued to be in good health, alert and engaging in conversations, and was still able to walk up steps. she became the oldest known living american in may 2004. shortly afterwards, on the occasion of her 114th birthday, she was presented with a proclamation signed by drake university president david maxwell. the university's vice president for institutional advancement, john willey, nominated her for an honorary degree. johnston died in worthington, ohio on december 1, 2004, at age 114 years, 117 days.