There are two options:
Take the Blue or the Green Line to Government Center. Walk down the stairs along the side of City Hall and cross Congress Street. We are across the street, you will see the large sign on our building, and note we are across from the New England Holocaust Memorial (six tall glass spires).
Or, take the Orange or Green Line to Haymarket, walk left on Congress Street, left on Hanover Street, and right onto Union Street.