Using the Michigan Syndromic Surveillance System changes in emergency department (ED) volume are being monitored as health insurance coverage expands through the Healthy Michigan Plan (HMP), which provides healthcare coverage to low-income adults. Seasonally adjusted monthly ED visits prior to and after the HMP implementation on April 1, 2014 are being compared. Preliminary data show increasing trends in ED utilization among populations with previously low levels of health insurance coverage. Increased health insurance coverage may expand healthcare service options beyond EDs. Alternatively, the demand for primary care services may exceed the level of access leading to increased ED utilization for primary care.