Copies of wills may be difficult as in Ireland it is basically only the indexes that remain. The Four Courts Fire in Dublin 1922 took most of these records.
Electoral Register voters 1837 for those registered 1832
Harvey P. DeMontmorency,Esquire Mountjoy Square, West House
Index of Wills:
W.R. DeMontmorency 1829 Executor Henry Devereaux
National Archives NA 1WR/1829/F/247, Vol. name 4/236/14
Harvey DeMontmorency, J.P. Castlemorres, Kilmaganny
(Justice of Peace)
There is supposed to be an 1894 directory entry Bray, Wicklow for a Rose DeMontmorency but I was unable to locate on the page I was given, went back a page and ahead a page! it should come just before DeSousa but it doesn't.
1901 Irish Census:
There are 20 DeMontmorency for all Ireland but mostly Dublin
If you want to go back to 1820-1839 the Tithe records might be of assistance.www.genealogy.nationalarchives.ie
Also PRONI in Belfast has information that might be relevant.www.landedestates.ie
has a few DeMontmorency Estates
a Frederick mentioned in Wicklow 1870 Baltinglass, Wicklow at Broughhillshouse owning 1,022 acres in Mayo and 428 in Co. Carlow.
Birth records for Wicklow are available on a not for profit,
History Foundation but not Carlow. Baltinglass however, is in Wickow and the Union of Baltinglass only covers part of Carlow.
On an old CD set from the Latter Day Saints, there are
Church of Ireland marriage records from 1845-1862 but only
Joseph Montmorency married Margaret Lillie 16 Aug 1855 recorded in South Dublin, Dublin
Fa: Harvey Montmorency Fa: John Lillie LDS FHL Film #101366
If part of the gentry often baptims and marriages took place
in Dublin sort of a social society thing. One in particular
would be a marriage of a daughter of a Fitzwilliam of Yorkshire who owned land in Yorkshire but he did own much land in Wicklow, bits of Carlow and Wexford. His daughter married in the Cathedral in Dublin. Most of the Gentry and
above had homes in Dublin as well as in the counties as well. They moved to their Dublin Houses for the 'social season'.
Have you tried the Registry of Deeds-Ireland its a rootsweb
freepages.genealogy website. Last updated Nov. 20, 2012