Numbers 1:26

1:26 From the descendants of Judah: According to the records of their clans and families, all the males twenty years old or older who could serve in the army were listed by name.

Numbers 2:9

2:9 All those numbered of the camp of Judah, according to their divisions, are 186,400. They will travel ¹  at the front.

Numbers 26:20

26:20 And the Judahites by their families were: from Shelah, the family of the Shelahites; from Perez, the family of the Perezites; and from Zerah, the family of the Zerahites.

¹ tn The verb is נָסָע (nasa’): “to journey, travel, set out,” and here, “to move camp.” Judah will go first, or, literally, at the head of the nation, when they begin to travel.