The Blue Hill Meteorological Observatory, also known as Great Blue Hill Weather Observatory, Blue Hill Weather Observatory, or simply the Blue Hill Observatory, in Milton, Massachusetts is the foremost structure associated with the history of weather observations in the United States. Located atop Great Blue Hill at the junction of Interstate 93 and Route 138 about 10 miles (16 km) south of Boston, Massachusetts, it is home to the oldest continuous weather record in North America, and was the location of the earliest kite soundings of the atmosphere in North America in the 1890s, as well as the development of the radiosonde in the 1930s.