John Lightfoot on Luke 1:39

[She went into the hill country, &c.] That is, to Hebron, Joshua 21:11. For though it is true indeed that the priests after the return from Babylon were not all disposed and placed in all those very same dwellings they had possessed before the captivity, yet it is probable that Zacharias, who was of the seed of Aaron, being here said to dwell in the hill country of Judah, might have his house in Hebron, which is more peculiarly said to be 'the city of Aaron's offspring.'