Rashi on the Former Prophets

And the remaining descendants of Kehos. They were the descendants of Moshe, the descendants of Yitzhar, Chevron and Uzziel.
From the families of the tribe of Ephraim. From the inheritance of the tribe of the descendants of Ephraim, these cities were alloted to them. They received cities from the portion of each tribe, as it is said: “Take more from a larger [portion], and less from a smaller [portion]; each person according to his inheritance, shall give of his cities to the Levi’im.

That will be mentioned by name. Since he had not mentioned earlier the names of the cities that were given to them, and he enumerates their names later, he therefore states [now], “these cities that will be mentioned by name.”

And Almon. In Sefer Divrei haYomim it is rendered: and Olemes this is similar to Bachurim which Yonason translates as Alomos.
and their open spaces around it. Two thousand amos on each side.