River estuary and the skyscrapers of Boston six miles (10 km) away. Both the neighboring house in which Hutchinson lived during the construction of his mansion and the barn of the estate still stand and are both privately owned. The last remnant of Unquity is the ha-ha wall, once a part of the estate's opulent gardens. Both Governor Belcher's house and Governor Hutchinson's field are on the National Register of Historic Places. After American independence Following the revolution, Milton continued to be a thriving agricultural and industrial town, greatly influenced both socially and economically by the prosperity of Boston and the newly-forged American identity. The town grew extremely wealthy in the late 18th and early 19th century with the booming China Trade and the industrialization of Massachusetts during the early Industrial Revolution. As a result, much of Boston's elite built opulent country estates set on vast grounds throughout the idyllic hills and meadows of the town's more rural sections. Like many other coastal American cities, high society would leave the cities for the summer, and in the case of Boston, many would move to Milton due to its rural qualities, proximity to Boston, its highly active mercantile wharf, and the families' factories in Lower Mills which allowed the tycoons to continue business in the summer months. Most of these estates were concentrated on Milton Hill, Brush Hill, and Upper Canton Avenue. Among the last remaining of these estates that is entirely intact is the W.E.C Eustis Estate at the base of the Blue Hills on Canton Avenue. The town was also home to America's first piano factory. Revolutionary Milton is the setting of the opening of the 1940 bestselling historical novel Oliver Wiswell by Kenneth Roberts. The Blue Hill Meteorological Observatory is located in the town, home of the nation's oldest continuously kept meteorological records. The Granite Railway passed from granite quarries in Quincy to the wharf of Milton on the Neponset River, beginning in 1826. It is often called the first commercial railroad in the United States, as it was the first chartered railway to evolve into a common carrier without an intervening closure. A centennial historic plaque from 1926 and an original switch frog and section of track from the railway can be found in the gardens on top of the Southeast Expressway (Interstate 93) as it passes under East Milton Square. The frog had been displayed at