Etymology

ME hauen could be explained as native, cp. OE hæfen, hæfene 'harbour, port, haven', but the OE word is usually explained as a loan from ON: the OE forms are recorded late, in contexts with plausible ON influence, and there are no attested ME spellings with <e> in the root syllable, even in dialects where OE /æ/ usually > ME /e/; for full discussion, see SPS 434-5, Dance 2003: 359, OED3.  The evidence for borrowing from ON hǫfn 'haven, harbour' (< PGmc *xaƀanō, cp. MLG hāvene, MDu haven, MHG habene) is thus circumstantial, but suggestive.

PGmc Ancestor

*xaƀanō

Proposed ON Etymon (OIcel representative)

hǫfn 'haven, harbour'
(ONP hǫfn (1) (sb))

Other Scandinavian Reflexes

Far havn, høvn, Icel höfn, Norw hamn, ODan hafn, Dan havn, OSw hamn, Sw hamn

OE Cognate

hæfen, hæfene 'harbour, port, haven'

Phonological and morphological markers

Summary category

BB2a

Attestation

From late OE (see etymological discussion and SPS); common and widespread in texts from early ME as well as scattered place-names and personal names (MED, OED, EPNE).

Occurrences in the Gersum Corpus

Cl 420; Pat 108; WA *1160

The instance at WA 1160 is only found in the D MS (but is preferred by TPD); the A MS reads <cite>. 

Bibliography

MED hāven (n.1) , OED3 haven (n.) , HTOED , Bj. 242, SPS 434-5, de Vries hǫfn (1), Mag höfn (1), Orel *xaƀanō, Kroonen *habanō-, DOE hæfen, hæfene, AEW hæfen(e) (2), EPNE hafn, hǫfn