The Idle Valley Nature Reserve, also known as Lound Gravel Pits or Sutton and Lound Gravel Pits, is a wetland Site of Special Scientific Interest (SSSI) situated north-west of the town of Retford in the Bassetlaw district of north Nottinghamshire.

This required huge volumes of fill, as between 2 and 3 metres (6.6 and 9.8 ft) of material had been removed over the entire site.

[1][2][3] In 2002, Natural England designated the site, formally known as the Sutton And Lound Gravel Pits, as an SSSI.

[4] Tarmac subsequently agreed to donate all of its land within the SSSI to the Nottinghamshire Wildlife Trust, to ensure its long-term care and management.

[7] In 2017, a new boardwalk was constructed adjacent to the visitor centre in order to improve access to the reserve, as part of a partnership between the Nottinghamshire Wildlife Trust and the Rotary club of Retford.

[8] The reserve is over 3 miles (4.8 km) long from the northernmost tip to the southern base of the site and covers over 1,100 acres (450 ha).

[14] A licence application for the reintroduction of beavers submitted by the Trust to Natural England was approved in June 2021.