ER stands for the emergency room, which is a part of the hospital. The ER receives patients who walk-in and also those who were transported by ambulance. On the other hand, Urgent care is the treatment center that basically staffed by the doctors, and just a few nurses to give treatment to minor illnesses.
Urgent care usually has longer hours of operation than the regular doctors’ office. It is actually very separate from a hospital, and it does not receive patients who were transported by ambulance, it only receives patients who walk-in.
While An Emergency Room stays open for 24 hours a day, that is, it is opened all day long and every day of the year. Patients are treated based on the sickest patients that were seen first. Patients are not attended to base on their time of arrival. Both patients that walk-in and those transported by ambulance are attended to.