This river is known as Baranduin and Brandywine River and it separates Bree-land from the Shire as it runs through the central and southern parts of Eriador. The large and wide river originates in Lake Evendim and soon it flows southwards past The Shire, Bree-land, and the Old Forest. About this region smaller streams contribute: The Núrsir flowing through the North Downs, The Water which runs from Yondershire through The Shire, The Stockbrook which springs from Green Hill Country to south of Stock, the Withywindle which flows through the Old Forest, and the Shirebourn which flows through the Southfarthing of the Shire. South of Old Forest it turns more to south-west and eventually empties into the Great Sea near Eryn Vorn.
Elves know this river as Baranduin, meaning "golden-brown river" in Sindarin.
The old Hobbit name for Brandywine River was "Branda-nîn" meaning "border water". Playful Hobbits sometimes refer to it as "Bralda-hîm" ("heady ale") in joking reference to the colour of the river.
The main crossing of Baranduin is the Brandywine Bridge along the Great East Road, with a secondary crossing via the Bucklebury Ferry between the Marish on the western bank and Buckland on the eastern bank.
The Tale of the Shipwrecked Mariners takes place along the river in mid-September each year.
-  Sink or Swim
-  Sunken Shipwreck
- [...] The Tale of the Shipwrecked Mariners
In the year 1601 of the Third Age (III 1601), two Fallohide brothers, Marcho and Blanco, lead a group of Hobbits west from Bree across the Brandywine Bridge, having obtained permission from King Argeleb II, the tenth King of Arthedain at Fornost on North Downs, to settle the unused land between the Brandywine and the Far Downs, thus establishing The Shire. King Argeleb II required only that the Hobbits acknowledge his rule, and keep repair of the roads and bridges that crossed through the Shire, particularly the Brandywine Bridge.
The crossing of the Brandywine to found the Shire marks the beginning of the Shire-reckoning, the system Hobbits use to record years. Years of the Third Age can be converted to Shire-reckoning by subtracting 1600; therefore the year III 1601 is the year S.R. 1.
In III 2340, the Hobbit Gorhendad Oldbuck traveled east across the Brandywine and settled there in the lands between the Brandywine River and the Old Forest thus establishing Buckland, the home of the Brandybuck family.
While most Shire-hobbits have an aversion to swimming and sailing, the Brandybucks sometimes enjoyed boating on the Brandywine River. In III 2980, an unfortunate accident while boating on the Brandywine River lead to the drowning of Drogo Baggins and Primula Brandybuck, leaving their son, Frodo Baggins, an orphan at age 12.
On September 22, III 3018, several Nazgûl crossed the Brandywine and entered The Shire in search of the One Ring which they knew to be in the possession of a Hobbit named Baggins. Three days later, on September 25, Frodo and his companions, Samwise Gamgee, Peregrin "Pippin" Took, and Meriadoc "Merry" Brandybuck, crossed the Brandywine River on the Bucklebury Ferry on their way to Crickhollow in Buckland only to find that when they reached the eastern bank a Nazgûl was searching for them on the western bank at the Bucklebury Ferry landing.
The Baranduin starts at the edge of Lake Nenuial as it passes beneath High King's Crossing.
As it keeps south, it creates the eastern border of the Shire.
The Brandy Hills take their name from the river.
The bridge to Stock is the only other constructed crossing of the river after High King's Crossing.
The Baranduin passes Buckland, where the famous Bucklebury Ferry provides another means to cross the river.
As it continues south from the Marish, shifting southeast for a stretch, the landscape around it becomes impassable and the only option is to swim.
For a long while, the Old Forest follows the left bank of the river. The Withywindle enters the Baranduin from the northern reaches of the forest.
The calm and wide river then passes into Cardolan, with the Southfarthing of the Shire on its right bank.
A rocky natural ford named Sarn Ford provides a direct crossing from the Southfarthing into the lands further east.
Though the river continues its journey toward Minhiriath and eventually the sea, access beyond Cardolan is prevented by a strong current.