Thank you for looking up those names for me. Unfortunately, they are not the people I am looking for. My grandmother, Mary Collins, migrated to Australia with her family in 1867 and she died here in 1948 in Dubbo, NSW. Isaac died in 1904, in the same area. I think the problem is that there were only a few Christian names used in the 19th century, so that Mary was very common, as was the Collins surname, particularly in Ireland.

This looks like Mary's parents wedding record.

IRELAND MARRIAGES, 1619-1898
Name Isaac Edward Collins
Spouse's Name Eliza Mc Elhinney
Event Date 27 Jun 1861
Event Place Templemore, Derry, Ireland
Father's Name Henry Collins
Spouse's Father's Name John Mc Elhinney

Indexing Project (Batch) Number M70224-7
System Origin Ireland-EASy
GS Film number 101428
Reference ID p242 ln219

Victoria, Australia, Assisted and Unassisted Passenger Lists
Name: Isaac Collins
Estimated birth year: abt 1827
Age: 40
Arrival Date: 18 Apr 1867
Arrival Port: Melbourne, Australia
Departure Port: Liverpool
Ship: Castlemaine
Nationality: Irish

also listed :

Eliza A 32
John 4
Eliz Walker 2
Mary infant

all are listed born ireland except Mary where it just state infant. Could she have been born at sea ?

I found one birth for a Mary in Letterkenny in 1866 she died in 1868 and neither list parents names

Ireland, Civil Registration Births Index
Name: Mary Collins
Date of Registration: 1866
Registration district: Letterkenny
Volume: 7
Page: 194
FHL Film Number: 101043

Ireland, Civil Registration Deaths Index
Name: Mary Collins
Estimated birth year: abt 1866
Date of Registration: 1868
Death Age: 2
Registration district: Letterkenny
Volume: 17
Page: 109
FHL Film Number: 101584

I tried looking for children born to Isaac and Eliza and found only this:

Name: Elizabeth Walker Collins
Gender: Female
Birth Date: 13 Mar 1864
Birth Place: Londonderry, Londonderry, Ireland
Father's name: Isaac Collins
Mother's name: Eliza Mcilhenny
FHL Film Number: 101086

Do you know the exact date of Mary's birth ? The family would have had to travel from Templemore, Derry, Ireland to Liverpool according to the ships place of departure unless the ship made pick ups in Ireland. The ship departure is note clear but I think it was 21 Dec 1866
State voyage 140 days. Was Mary born in Ireland while travelling to Liverpool or Liverpool could she have been born in Liverpool ? Sorry not many answers but a few things to look into.

Did Mary marry, where and who, approx year ?

Everything you have found is correct. I know that Mary was not born on the ship, she was born in Ireland -she told my father (her son) that she was born in Letterkenny (this is probably because Eliza, her mother, was from Donegal)and was 1 year old when they left. Although she was born in Letterkenny, the family lived just over the border in Derry. If the birth was registered, it would have either been in Donegal or Derry. I suspect however that Isaac and Eliza may not have registered her birth because they were close to emigrating to Australia and it was overlooked. I found it very annoying that I could find birth details for her sister Elizabeth Walker Collins, but nothing at all about Mary.

Mary married John Robertson(a Scot) in 1890 in Dubbo, NSW Australia. I must thank you for your interest in this. It's much appreciated.

I have also tried to find out the parish where her baptism would be registered, but all I know is that the family was Church of Ireland (Church of England), but have no idea what parish it was.

http://www.rootsireland.ie/

There is the site above but its view by subscription.

Also these:

http://www.irishgenealogy.ie/en/

http://www.irishancestors.ie/?page_id=1526

There are more just google

You might find something here. Letterkenny see Conwall and Leck.

Parish, Church, or Chapel Diocese County Baptisms Marriages Burials

RCB Leck Raphoe Donegal 1878-1975* 1846-1959 1878-1900
RCB Conwal Raphoe Donegal 1876-1951* 1845-1988 1878-1906

* from this I assume there were no baptisms registered before 1878

RCB = Original records held by the Representative Church Body Library, Churchtown, Dublin 14

It suggests also looking here: http://www.proni.gov.uk/

TABLE OF CHURCH OF IRELAND PARISH REGISTERS THROUGHOUT IRELAND
(Baptisms, Marriages, Burials & copies)


http://ireland.anglican.org/cmsfiles/pdf/AboutUs/library/registers/ParishRegistersTable.pdf

Thanks for that. I will start looking.