Barnsley Warren (grid reference SP055064) is a 61.3-hectare (151-acre) biological Site of Special Scientific Interest in Gloucestershire, notified in 1954 and renotified in 1984. The site is also included in A Nature Conservation Review. It lies in a steep-sided dry valley, east of the A429, northeast of Cirencester in the Cotswolds. The site is listed in the 'Cotswold District' Local Plan 2001-2011 (on line) as a Key Wildlife Site (KWS). There are seven units of assessment and the Gloucestershire Pasqueflower Reserve is unit 4.