Like many Domesday measures, there is no certainty about the extent of the league, or even whether it was a linear or areal unit. Though there may normally have been 12 furlongs to the league, for instance, it has been argued that the Wiltshire league was 15 furlongs long, that of Worcestershire only four. The league also appears sometimes to have been used as a synonym for the mile (which does not occur in Great Domesday), and vice-versa. Many Domesday statements imply that the league, like the furlong, could be a measure of area.
For more detail, see J.H. Round, 'Introduction to the Worcestershire Domesday', Victoria History of the county of Worcestershire, vol. 1, edited by J.W. Willis-Bund (1901), pages 282-323; R.R. Darlington, 'Introduction to the Wiltshire Domesday', Victoria History of the county of Wiltshire, vol. 2, edited by R.B. Pugh and E. Crittall (1955), pages 42-177; and Philip Grierson, 'Weights and measures', Domesday Book: studies, edited by Ann Williams and R.W.H. Erskine (1987), pages 80-85).