When the Bnai Yisrael left Egypt, many converts left with them.
וְגַם עֵרֶב רַב עָלָה אִתָּם וְצֹאן וּבָקָר מִקְנֶה כָּבֵד מְאֹד:
And also, a great mixed multitude went up with them, and flocks and cattle, very much livestock.
ערב רב: תערובות אומות של גרים
a great mixed multitude: A mixture of nations of proselytes.
Now parshat Bamidbar spells out in great detail exactly how the 12 tribes camped:
Starting from Bamidbar 2:2 (and onwards)
אִישׁ עַל דִּגְלוֹ בְאֹתֹת לְבֵית אֲבֹתָם יַחֲנוּ בְּנֵי יִשְׂרָאֵל מִנֶּגֶד סָבִיב לְאֹהֶל מוֹעֵד יַחֲנוּ:
The children of Israel shall encamp each man by his division with the flag staffs of their fathers' house; some distance from the Tent of Meeting they shall encamp.
So that made me wonder: where did the converts (erev rav) camp? Do any of the meforshim ask this question?
(Just thinking out loud:)
On one hand it seems hard to believe that they were 'shunned' outside all the camps since we see that the erev rav had somewhat of an influence on the Bnai Yisrael - e.g. Regarding the sin of the golden calf: See Rashi on Shmot 32:7 ..."They have acted corruptly and have corrupted [others]"
(Edit: It just hit me that the golden calf incident happened before the Bnai Yisrael were commanded how to camp.... so I'm not sure about the above paragraph.)
On the other hand, it seems hard to believe that the tribes would let converts camp in their camp - take the account of the mekallel - Rashi on Vayikra 24:10 -
The Baraitha states: He “went out” of Moses’ tribunal [with a] guilty [verdict. How so?] He had come to pitch his tent within the encampment of the tribe of Dan. So [this tribe] said to him, “What right do you have to be here?” Said he, “I am of the descendants of Dan,” [claiming lineage through his mother, who was from the tribe of Dan (see verse 11)]. They said to him, “[But Scripture states (Num. 2:2): ‘The children of Israel shall encamp] each man by his grouping according to the insignias of his father’s household,’” [thereby refuting his maternal claim]. He entered Moses’ tribunal [where his case was tried], and came out guilty. Then, he arose and blasphemed. — [Vayikra Rabbah 32:3]