York Street is a street in Marylebone in Central London. Located in the City of Westminster, it runs west from Baker Street in a straight line until it begins curving when it becomes Harcourt Street towards the Old Marylebone Road. It crosses a number of streets including Seymour Place, Upper Montagu Street and Gloucester Place. It was laid out in the eighteenth century as part of the grid-like pattern of the area, developed from the Portman Estate as affluent housing.