Its source lies in Kirkby-in-Ashfield, and from there it flows north east through Mansfield (which takes its name from the river), Edwinstowe and Ollerton, these being the heart of the Sherwood Forest area.

It becomes known as Whitewater near the village of Walesby and connects to the River Meden temporarily where the Robin Hood Way crosses them.

William Cavendish-Bentinck, 3rd Duke of Portland, encouraged the building of textile mills to relieve unemployment and poverty.

The river rises on the north side of Kirkby-in-Ashfield, just to the south of Sutton Parkway railway station.

[3] At the exit from the reservoir, the river is crossed by Kings Mill viaduct, built around 1819 for the Mansfield and Pinxton Railway.

A local newspaper described it as "the beautiful five-arched bridge, constructed under the direction of Mr. Jessop, the engineer", when reporting the opening.

[7] After crossing under some minor roads and Sheepbridge Lane, where there was another eighteenth-century textile mill, repurposed as a joinery works, and then an internet gaming centre[8] the river is spanned by the disused Drury Dam railway viaduct,[1] this one built in 1875, and consisting of ten round arches, constructed of brick and rock-faced stone.

[9] Part of it spans the Quarry Lane local nature reserve, on the south bank of the river, where a sculpture created by Lewis Morgan was installed in December 2009.

[12] Next, the river passes through Carr Bank, with woodland to the east, and a large sewage treatment works to the west.

After passing under the A6117 road, the river enters Maun Valley Park, a local nature reserve covering 42 acres (17 ha), which includes water meadows and other wetland habitats.

Approaching Clipstone, Cavendish Woods lie to the south east, while extensive fish ponds are located on the other bank.

This was situated to the north of the town, probably near to the later Stanton's Mill, and was part of the process for making woollen cloth.

In an attempt to remedy the situation, William Cavendish-Bentinck, 3rd Duke of Portland, who was the landowner, and who later became Home Secretary, organised a programme of building water-powered spinning mills along the river.

The miller, William Smith, negotiated with the Duke, and in 1785 he sold the corn milling equipment and refitted it for working with cotton.

Having also refitted Field Mill in the autumn, he started a Sunday School in 1786, so that his young workers would be equipped with basic reading and mathematical skills, as well as moral instruction.

The site had previously been occupied by a water-powered bark mill, and remained in the ownership of the Duke of Portland.

In 1867, Bradshaw and Sansom negotiated a new 14-year lease with the Duke, which included the supply of water from King's Mill reservoir, but they became bankrupt during the following year.

It was taken over by James Bownes, who formed a limited company to operate it, and it remained in use until 1960, when the firm moved to new premises, and the site was redeveloped by the Mansfield Brewery.

There are several components that are used to determine this, including biological status, which looks at the quantity and varieties of invertebrates, angiosperms and fish.

Like most rivers in the UK, the chemical status changed from good to fail in 2019, due to the presence of polybrominated diphenyl ethers (PBDE), perfluorooctane sulphonate (PFOS) and mercury compounds, none of which had previously been included in the assessment.