Albert Barnes Commentary 1 Samuel 11:8

"And he numbered them in Bezek; and the children of Israel were three hundred thousand, and the men of Judah thirty thousand." — 1 Samuel 11:8 (ASV)

He numbered them - This was done to see who was absent .

Bezek has been conjectured to be the name of a district rather than a town. Two villages retained the name in the time of Eusebius, located 17 miles from Nablous on the way to Beth-shean.

The children of Israel and the men of Judah - This phrasing seems to come from a later time, perhaps after the establishment of the two kingdoms of Israel and Judah. Here, Israel (including Benjamin) is in a ten-to-one ratio compared with Judah. This is approximately the correct proportion.