Numbers 3:19-23

and the sons of Kohath by their families: Amram and Izhar, Hebron and Uzziel;

and the sons of Merari by their families: Mahli and Mushi. These are the families of the Levites according to their fathers’ households.

Of Gershon was the family of the Libnites and the family of the Shimeites; these were the families of the Gershonites.

Their numbered men, in the counting of every male from a month old and upward, their numbered men were 7,500.

The families of the Gershonites were to camp behind the tabernacle westward,