At Whitwell there are watercress beds which have existed since Roman times[citation needed] and these are fed by the same springs.

[3] Etymological connections have been suggested by academic philologists with the River Mint in Westmorland and with North Mymms in south Hertfordshire.

There have been suggestions of it being named after a Celtic deity, though no academic sources have been cited for this and the speculation probably stems from a comparison with etymology for the nearby River Beane.

Eilert Ekwall believes the Old English version of the name was Memere or Mere (Mære), and that, given the dubious nature of early forms, no etymology can realistically be attempted.

[4] Archaeologist Keith Fitzpatrick-Matthews has written[5] that the Mimram's name is meaningless in Old English and therefore must have Brittonic origins.

He writes: "Mimram" seems to contain Brittonic *mimo-, ‘speaking, murmuring, mumbling’, and *aramo-, ‘gentle, calm, quiet’.

The upper reaches of the Mimram are crossed only occasionally by small road bridge or fords (eg at Welwyn and Codicote Bottom).