Alexandra Marine and General Hospital in Goderich have declared a COVID-19 outbreak.
They announced on Facebook Tuesday that one patient on the ICU-Inpatient first floor had tested positive.
They say the unit is now closed until further notice.
Emergency and urgent surgeries will continue to operate but anyone admitted to the intensive care unit will need to isolate.
No other inpatient or ambulatory services are being affected.
They say public health have been notified, and contact tracing and testing for individuals on the unit is taking place.