The Children's Hospital of Philadelphia, also known by its acronym CHOP, is a children's hospital in Philadelphia, Pennsylvania. Its primary campus is located in the University City neighborhood of West Philadelphia on the campus of the University of Pennsylvania. The hospital has 594 beds and more than one million outpatient and inpatient visits annually. It is one of the world's largest and oldest children's hospitals and the first hospital dedicated to the healthcare of children. CHOP has been ranked as the best children's hospital in the United States by U.S. News & World Report and Parents Magazine in recent years. As of 2020, it was ranked number one in the nation by U.S. News & World Report for three out of ten specialties. The hospital treats infants, children, teens, and young adults aged 0–21. The hospital also treats adults that would benefit from advanced pediatric care. The hospital is located next to the University of Pennsylvania and its physicians serve as the pediatrics department of the Perelman School of Medicine at the University of Pennsylvania. History First hospital 1855–66 In 1855, Philadelphia had a population of about 460,000, and recorded 10,507 deaths. Leading causes of death were smallpox, typhoid, and scarlet fever. In the worst month of 1855, 300 children under 12 years old died, primarily of infectious diseases. A Philadelphia physician, Dr. Francis West Lewis, inspired by a visit to the new Great Ormond Street Hospital for Sick Children in London (founded 1852), enlisted Drs. T. Hewson Bache and R. A. F. Penrose Sr. to found the first children's hospital in North America. On November 23, 1855, the following small advertisement appeared in the Philadelphia Public Ledger: The Children's Hospital—located on Blight Street, running from Pine to Lombard, below Broad, is now open for the reception of Patients. Children suffering from Acute Diseases and Accidents will be received free of charge. A dispensary, for sick children, is also attached to the Hospital and will be open at the same place every day, (Sundays excepted from 11 to 12 o'clock, when advice and medicine will be given free of charge.) The first location of the original Children's Hospital was a small building on Blight Street (now Watts St). The hospital consisted of 12 beds and a dispensary. That year they recorded 67 inpatient admissions and 306 outpatient visits. Second hospital 1866–1916 Children's Hospital was relocated to 22nd Street between Locust