A brownstone is a type of residential building commonly found in urban areas, particularly in the northeastern United States. It is typically made of brown sandstone, which gives it its name. Brownstones are often characterized by their distinctive architectural features, such as stoops, large windows, and decorative cornices. They usually have multiple stories and can be single-family homes or multi-family units. These buildings became popular in the 19th century, especially in cities like New York City and Boston. Many brownstones have been preserved and renovated, making them sought-after properties due to their historical charm and proximity to city amenities.