Charles Street is the name of a north-south street in the city center of Boston, Massachusetts. It begins in the north at Leverett Circle, where it connects with and Monsignor O'Brien Highway. Science Park station on the MBTA Green Line is located there. Charles Street runs south and gives its name to the Charles/MGH station on the MBTA Red Line, connecting via the Charles Circle rotary to and the Longfellow Bridge which leads to Cambridge. This segment is a one-way street, with traffic heading northwards.