Brownstone is a brown Triassic–Jurassic sandstone that was historically a popular building material. The term is also used in the United States and Canada to refer to a townhouse clad in this or any other aesthetically similar material. Types Apostle Island brownstone In the 19th century, Basswood Island, Wisconsin was the site of a quarry run by the Bass Island Brownstone Company which operated from 1868 into the 1890s. The brownstone from this and other quarries in the Apostle Islands was in great demand, with brownstone from Basswood Island being used in the construction of the first Milwaukee County Courthouse in the 1860s. Hummelstown brownstone Hummelstown brownstone is extremely popular along the East Coast of the United States, with numerous government buildings throughout West Virginia, Pennsylvania, New York, Maryland, and Delaware being faced entirely with the stone, which comes from the Hummelstown Quarry in Hummelstown, Pennsylvania, a small town outside of Harrisburg, Pennsylvania. The Hummelstown Quarry is the largest provider of brownstone on the east coast. Typically, the stone was transported out of Hummelstown through the Brownstone and Middletown Railroad. Portland brownstone Portland brownstone, Connecticut River Brownstone, is also very popular. The stone from quarries located in Portland, Connecticut and nearby localities was used in a number of landmark buildings in Chicago, Boston, New York City, Philadelphia, New Haven, Hartford, Washington D.C., and Baltimore. New Jersey brownstone Quarries from the Passaic Formation in northern New Jersey once supplied most of the brownstone used in New York City and New Jersey. South Wales brownstone Devonian aged sandstone is commonly used in Southern Wales. Use in urban private residences There are many brownstones throughout numerous New York City neighborhoods, especially in the Brooklyn neighborhoods of Park Slope, Clinton Hill, Fort Greene, Cobble Hill, Carroll Gardens, Boerum Hill, Gowanus, Windsor Terrace, Prospect Heights, Crown Heights, Brooklyn Heights, Bedford Stuyvesant, and Sunset Park. Smaller concentrations exist in parts of Bay Ridge, Williamsburg, Bushwick, Greenpoint, and Prospect Lefferts Gardens. Brownstones are also scattered throughout Manhattan from the Lower East Side to Washington Heights, with notable concentrations in the Upper West Side, Upper East Side, Harlem and East Harlem. In Queens and The Bronx, the historic districts of Long Island City and Mott Haven also host many brownstones. Brownstones also predominate in some Hudson County neighborhoods directly across the Hudson River from Manhattan, especially in Hoboken and around Van Vorst Park and Hamilton Park in Jersey