The FSF has moved a few times.
* 675 Mass Ave, Cambridge.
* 59 Temple Place, Boston
* 51 Franklin St, Boston
* 31 Milk Street, Boston
The first address wasn’t around for too long, but does still exist. It’s an office building above a bank in Central Square, Cambridge right above the Red Line stop.
The second address was around for a long, long time. A few years ago, the building was demolished and turned into a hotel. I don’t know if 59 Temple Place is still a valid address or not. For this one, I found many of most frequent places and filed bugs to get it updated. Greg K-H helped me update the kernel and many of the issues I opened got resolved with other projects. Worth noting too that the FSF had two different offices in the same building but mail would go to the building. Mail did forward from here to the next address for a while, but I’m not sure if it’ll forward again to the latest address.
51 Franklin St is just around the corner from 59 Temple Place. When they moved here, many staff were able to walk their stuff over to the new office. This one finally closed last year. I worked here my entire time at the FSF.
The final one is a PO Box but also around the corner from 51 Franklin St.