Hello Murph,
An Irish agricultural land record called the Tithe Applotment books shows that a Michael Murphy leased farmland in the townland of Ballinacourty, Civil Parish of Stradbally, County Limerick. Stradbally is also the civil parish where Castleconnell was located in the 19th century.
Also recorded in Ballinacourty in the Tithe Applotment Books were James Murphy and Tim Murphy. See the Tithe Applotment Book index for the three Murphys at: https://tinyurl.com/bdraed7y
A copy of the original Tithe Applotment Book entry for Ballinacourty is a challenge to read because of the handwriting, but shows the Tithe record for Ballynacourty was compiled in May and November of 1832. See the attachment.
The green arrows show the location of Js (James) Murphy, Michl (Michael) Murphy, and Tim Murphy on the tithe page. James was actually recorded twice in Ballynacourty. The Murphys may have been brothers.
Tithes were collected in the 32 counties of Ireland to support the established Church of Ireland.
For more information and to search the Tithe Applotment Books go to the National Archives of Ireland link at: https://titheapplotmentbooks.nationalarchives.ie/search/tab/home.jsp
The Michael Murphy in the Tithe Applotment Books for Ballynacourty could be your ancestor, as Ballynacourty, according to a Google Map, is 2.2 miles south of Castleconnell by the shortest route. See: https://tinyurl.com/yh8dyyk7
Castleconnell on the map is indicated by the red teardrop icon.
For a Google Street View of Main Street, Castleconnell, see: https://tinyurl.com/5ardvbdt
Here is a Google Street View of Ballynacourty: https://tinyurl.com/nhb24wbu
I also found Ballyncourty and Castleconnell on an Ordnance Survey Map of County Limerick. The map is from the 1829 to 1842 time period, which covers the time that Michael, James, and Tim Murphy were recorded in the Tithe Applotment Books.
The maps are from the Tailte.ie website, and are attached to this reply.
On the Ordnance Survey Map for Castleconnell, you'll see the location of the Post Office. The river to the west of Castleconnell is the Shannon River.
In the 19th century Castleconnell, because of its close proximity, would have likely been the post town assigned for Ballynacourty, which is why the Murphys in New Zealand may have named Castleconnel as their town in Ireland. See Samuel Lewis's 1837 publication of "A Topographical Dictionary of Ireland" from the Library Ireland website for more information about Ballynacourty:
https://www.libraryireland.com/topog/C/Castleconnel-Clanwilliam-Limerick.php
Limerick City Centre is not far away from Ballynacourty, as this Google Map shows the distance, by the shortest route, to be 6.5 miles: https://tinyurl.com/3ymta473
This means it's not out of the realm of possibility that the John Murphy baptized in St. John's Church, Limerick City, on 20 June 1839, is your ancestor.
A copy of John's original baptism record from the National Library of Ireland is attached to this reply. In addition to showing that his parents were Michael Murphy and Honora Howard, the baptism record also shows that John's sponsors, or godparents, were Richd (Richard) Waller and Anna Howard. Anna Howard may have been Honora's sister. The priest who baptized John was the Rev. M Clark.
The combined Tithe Applotment Book entry for Michael Murphy, the close proximity of Ballynacourty to Castleconnell and Limerick City, and the 1839 baptism record for John Murphy, present circumstantial evidence, not direct evidence, that John, Michael, and Honora Howard Murphy, are your ancestors.
Murphy is and was the most populous name in Ireland, and so hopefully you'll someday be able to uncover a record showing who John's mother was (direct evidence), to differentiate your Murphy ancestors from the many other Murphys in 19th century County Limerick, Ireland.
Have a fantastic time in Ireland.
Best Wishes,
Dave Boylan
SOURCES
National Archives of Ireland: Tithe Applotment Books
Google Maps
Google Street Views
Tailte.ie: Ordnance Survey Maps
Samuel Lewis: A Topographical Dictionary of Ireland
National Library of Ireland