1911 Census reference to Edward WILLIAMS - born in Ireland

[annclare]

If you accept Kildalkin as probable it is on the borders of Co Dublin and Kildare. For what its worth I think it is likely The Poor law Union and registration district for that area in Kildare would be Celbridge. There is a birth registration in 1865 for an Edward Williams in Celbridge district that might fit.

However it may prove difficult to confirm if this is the correct Edward Williams when you haven't a father's name.
annclare

[Bockety]

I agree. The Poor Law Unions of 1838 also became Civil Registration Districts for births. The Celbridge birth  I linked earlier could have been in  what is now South Dublin ...ie across the border from then and now Kildare

see http://www.irish-genealogy-toolkit.com/image-files/registrardistrictsmapsouth2.jpg

Births were registered ( certainly in the mid/late 19th century) by CRD

http://www.irish-genealogy-toolkit.com/Ireland-civil-registration.html

Each CRD was under  a Superintendent Registrar.

Rathcoole ( the barony of I think) was under Celbridge. See.

http://genealogyresearch.org.uk/IRL_RegistrationDistricts1871.pdf

I reckon that is he But do the names WILLIAM or HENRY run in your family OP 

See why

http://www.askaboutireland.ie/griffith-valuation/index.xml?action=doNameSearch&Submit.x=49&Submit.y=10&Submit=Submit&familyname=williams&firstname=First+Name&baronyname=NEWCASTLE&countyname=DUBLIN&unionname=&parishname=