Question: The mishna says that the pesach was done in 3 groups, in the Azarah.
The Azara without qualification usually means Ezrat Yisrael. T
his is also implicit in the comments of the Yachin uBoaz and the RSH"SH on the mishna. The Ezrat Yisrael was 11 amot by 135 amot, roughly 20 ft by 200 feet, or 4,000 square feet. Assuming (very cramped) that a person takes up 1 square foot, that is room only for 4,000 people at a time (ignoring the space for the sheep and goats).
So it seems that 1. the story on 64b about 1,200,000 pesachs must be an exageration, but, more importantly 2.even with a smaller population, how was there enough room?
(a) I passed your question on to Rabbi Yehudah Landy (www.neveh.org) who responded as follows:
"It is certainly permitted for a Yisrael to enter into the Ezras Kohanim, and even between the Ulam and the Mizbe'ach when there is a need to do so, as the Mishnah says in Kelim at the end of the first Perek. However, this will not answer your question, because it still does not give sufficient room for such a large number of people, for the entire azrah is 187 X 135 Amos, in which the Beis ha'Mikdash takes up 100 X 70 (or actually a little bit more than that), leaving only approximately 24,500 sq. Amos, besides the Lishkos and the area of the Mizbe'ach and other items. All of Israel brought their Korbanos Pesach with them, and every animal must certainly require more than one squared Amah, and thus your question remains.
"I heard from Rabbi Zalman Koren, the foremost expert in our generation on all matters of the Mikdash, that your question has been addressed by a gentile scholar by the name of Hoyt who was an engineer and who wrote a scholarly book on the topic ("More Places for People," Charles K. Hoyt, 1983, McGraw-Hill, New York).
"In order to answer your question, [(1) it must be that the Gemara is indeed making an exaggeration, as you suggested, or (2) a miracle occurred so that a large amount of animals could be contained within a small amount of space, as we find in Gitin (57a) and in Avos (5:5). (3)] Hoyt suggests -- and Rav Koren agrees that this is a possibility -- that the "Azarah" mentioned here includes the area north of the Azarah on Har ha'Bayis. The members of each group would enter the Azarah from the south and exit to the north and wait there."
(There are a number of comments to make on this approach, but such discussion is beyond the scope of this forum.)
Best wishes, and thanks for the question,
There is no reason to look for miracles! Instead look at the Halacha: It isd within the jurisdiction of the Sanhedrin to change the limits of the Azara - so that may well be what they did: 0n the 13th of Nissan they enlarged the Azara to cover the area needed by the already in Jerusalem plus those still expected. At some later date - perhaps after Hol Hamoed - they restored the Azara to its original size! Yeshayahu HaKohen Hollander
Your suggestion is excellent! However, we do not find anywhere that it is possible to remove the Kedushah of a place that was sanctified and made into part of the Azarah. While the Gemara teaches how to add to sanctified areas, there is no description how to take away from them. Furthermore, "Ma'alin b'Kodesh v'Lo Moridin" would require that the area remain sanctified.