Tribe of Judah: At Bezek
Source: Nav
1 Samuel 11:8
And when Saul numbered them at Bezek, there were 300,000 Israelites and 30,000 men of Judah.
2 Samuel 24:9
And Joab reported to the king the total number of the troops. In Israel there were 800,000 men of valor who drew the sword, and in Judah there were 500,000.