Well, obviously it is forbidden if the bishop does not permit it to be celebrated. And given all the grexxing about trying to get an indult mass in the USA, one has to suspect that refusal dominates permission.
Certainly in the DC area it is hard to find one.
The Tridentine Mass is not forbidden, as I have stated it can not forbidden.
"Furthermore, by these presents [this law], in virtue of Our Apostolic authority, We grant and concede in perpetuity that, for the chanting or reading of the Mass in any church whatsoever, this Missal is hereafter to be followed absolutely, without any scruple of conscience or fear of incurring any penalty, judgment, or censure, and may freely and lawfully be used. Nor are superiors, administrators, canons, chaplains, and other secular priests, or religious, of whatever title designated, obliged to celebrate the Mass otherwise than as enjoined by Us
." - QUO PRIMUM Pope St. Pius V - July 14, 1570
No bishop can forbid a priest from celebrating the Tridentine Mass, even John Paul II admitts this:
"Pope John Paul II, in 1986, asked a commission of nine cardinals two questions. Firstly, did Pope Paul VI, or any other competent authority, legally forbid the widespread celebration of the Tridentine Mass in the present day? The answer given by eight of the cardinals in 1986 was that, no, the Mass of Saint Pius V has never beeen suppressed. I can say this; I was one of the cardinals.There was another question, very interesting. Can any bishop forbid a priest in good standing from celebrating a Tridentine Mass again? The nine cardinals unanimously agreed that no bishop may forbid a Catholic priest from saying the Tridentine Mass. We have no official publication and I think that the Pope would never establish an official prohibition ... because of the words of [Pope St.] Pius V, who said this was a Mass forever
." - ALFONS CARDINAL STICKLER, Prefect of the Vatican Archives and Library
Now whether or not a priest needs premission from the Bishop to celebrate the Tridentine Mass publically is a whole other issue, and an interesting debate. However, every priest has the right to celebrate the Tridentine Mass, and every priest will forever have this right.
As for the DC area:
St. Mary Mother of God (Old St. Mary) Church
Immaculate Medal Shrine, 727 5th St. N.W., Washington, DC 20001
Fr. David Conway, (202) 289-7770, 289-7771, fax 408-1989
Diocese, Sunday 9 am, 2nd Sundays of the Month 5 pm, Holydays 7:30 pmhttp://www.parishes.org/marymothergod.html
St. Francis de Sales
7185 Bendidct Avenue, Bendict, MD 20612-0306
Fr. Saverio T. Vitturino, (301) 274-3416
Diocese, Sunday 11 a.m.http://www.parishes.org/francisdesalesbenedict.html
114 West Saratoga Street, Baltimore, MD 21201
Fr. Arthur Bastress, (410) 685-6090
Diocese, Sunday 11:30 a.mhttp://www.archbalt.org/content.asp?id=299&parishId=2