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Michael J. Tilstra serves as Chief Executive Officer of Iroquois Memorial Hospital, bringing more than 30 years of leadership experience in business administration, community development, and public service. A lifelong resident of Iroquois County, Tilstra has strong ties to the community and a deep commitment to ensuring access to quality healthcare for the region.
Born at Iroquois Memorial Hospital and raised in the area, Tilstra currently resides in Onarga, Illinois. He earned a Bachelor of Science in Mathematics from Western Illinois University and later completed his Master of Business Administration from Olivet Nazarene University. After completing his education, Tilstra chose to remain in the area to serve the community that helped shape him.
Throughout his career, Tilstra has held numerous leadership roles in local organizations and public service. He served for more than two decades in business administration at Nexus-Onarga Academy and dedicated 16 years as the Village President of Onarga. His commitment to community leadership also includes service as Chamber President, Commissioner for the Onarga Fire Protection District, Federated Bank Trustee, and as a member of the Iroquois Development Association Board.
Tilstra is passionate about community engagement, economic development, and strengthening the organizations that support quality of life in Iroquois County. His leadership reflects a strong belief in collaboration, transparency, and investing in the long-term health and well-being of the region.
Family and community are central to Tilstra’s life. He and his wife, Amy, have three sons—Ryan, Aiden, and Collin. In addition to his professional responsibilities, Tilstra enjoys mentoring and supporting local youth and has spent many years coaching boys’ and girls’ sports in the Iroquois West system.
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Denise Graves, RN, MBA, serves as Chief Nursing Officer at Iroquois Memorial Hospital, a role she began in January 2025. With nearly 30 years of experience in healthcare, Graves brings a strong background in patient care, nursing leadership, and healthcare education to the hospital and the communities it serves.
Graves began her career in healthcare as a certified nurse aide and advanced through the profession to become a licensed practical nurse and later a registered nurse. She spent many years caring for patients and leading nursing teams at OSF Saint James Medical Center in Pontiac, Illinois, gaining experience in areas including emergency care, obstetrics, medical-surgical services, and skilled nursing.
In addition to her clinical work, Graves has held leadership roles in long-term are and post-acute settings, serving as Director of Nursing, Clinical Consultant, VP of Clinical and Nursing Home Administrator. Her leadership focuses on supporting nursing staff, maintaining high standards of patient care, and ensuring safe, high-quality services for patients and families.
Graves also has a passion for mentoring the next generation of healthcare professionals. She previously served as a nurse educator at Heartland Community College in Normal and Livingston Area Career Center in Pontiac, where she taught health science and emergency medicine courses while helping students explore careers in healthcare.
She earned her Associate of Science in Nursing from Heartland Community College in Normal, Illinois, and later completed both a Bachelor of Science in Healthcare Management and a Master of Business Administration from Franklin University in Columbus, Ohio.
As Chief Nursing Officer at Iroquois Memorial Hospital, Graves is dedicated to supporting the hospital’s nurses and clinical teams while ensuring patients receive compassionate, high-quality care close to home.
