1 February 1808
The district of Clanwilliam celebrates its second centenary on 1 February 2008. On 1 February 1808 the territory north of the Great Berg River, at the foot of the Cedarberg Range, was annexed to the new district of Tulbagh, proclaimed in 1804. At the same time the area was declared a separate sub-drostdy, with its magisterial seat at Jan Disselsvlei, a farm bought for this purpose from S. van Reenen. The region was renamed the district of Clanwilliam in 1841, in honour of the father-in-law of Sir John Cradock, the Earl of Clanwilliam.
References

Potgieter, D.J. et al. (eds) (1970). Standard Encyclopaedia of Southern Africa, Cape Town: NASOU, v. 3, p. 248.