Chalkshire is a hamlet in the parish of Ellesborough(where the 2011 Census population was included), in Buckinghamshire, England. It is situated on the road that runs from Butlers Cross to Terrick.
Map of Chalkshire, Aylesbury, UK
The hamlet name is fairly modern, and is quite literal in meaning. It refers to the composition of the nearby Chiltern Hills, at the foot of which the hamlet stands.
References
Chalkshire Wikipedia(Text) CC BY-SA