According to a recent analysis of data from the 2009-2010 National Hospital Ambulatory Medical Care Survey

• The emergency departments (EDs) that patients visited were located an average of 6.8 miles from the patient’s home, although the nearest ED was an average of 3.9 miles from the home
• 43.8% of all ED visits occurred at the ED closest to the patient's home
• Only 37.2% of ED visits within metropolitan areas took place at the closest ED, compared with 70.1% of visits outside of metropolitan areas
• In metropolitan areas, the average wait time for being seen (by a physician, physician’s assistant, or nurse practitioner) at the ED closest to a patient’s home was 52.3 minutes, compared withan average wait time of 62.3 minutes for visits to EDs that were farther away

Source: "Emergency Department Visits and Proximity to Patients’ Residences, 2009–2010," Centers for Disease Control and Prevention, NCHS Data Brief Number 192, March 2015, http://www.cdc.gov/nchs/data/databriefs/db192.htm