It is claimed to have given its name to the town of Braintree, although it seems that the name ‘Braintree’ is older, and that the river name is a back formation from the town name; Braintree lies on a low ridge between the Brain and the River Blackwater.
The brook rises near the village of Bardfield Saling.
Below Braintree the Brain joins the Blackwater in Whet Mead in Witham.
[1] In 2001, a "flood park" was planned to reduce the risk of overflow from the river.
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