The Chaddock surname is relatively uncommon. In North America it is found in Atlantic Canada and in Ontario, Manitoba, and BC. In the United States the Chaddock name seems to have been present much earlier than in Canada. One branch emigrated to Canada in the early 1900s out of Biddulph, Staffordshire, England. Chaddocks have long history in the area between Manchester and Liverpool although the male line seems to have ended around the time Chaddocks appeared in the Biddulph/Congleton area of Staffordshire. No connection is known.
The origin of the surname is not clear. Some feel it came from 'Shade Oak' to Shaydocke to Chaddock. Other theories exist. It may have arisen independently several times or may be derived from Chadwick or other similar forms.