Hæg

According to the Old English Dictionary:

hæg

a fence; a hag, an enclosure :-- Terram nominatam Haeg, C. D. i. 49, 23. The word is found forming the first part of local names, Hægdún, Hæghyll, Hægleá; also in other words, hæg-steald, hæg-þorn. See, too, ge-hæg, and cf. haga; hecg, hecge, hege. hæg