If you ever find yourself with nothing to do, you could use the online Ordnance Survey maps to follow the entire course of the Grand Canal from Dublin to the Shannon, starting here and switching between the Historic 6″ (roughly 1840) and the Historic 25″ (roughly 1900). You have to zoom in all the way to see the words and the details, so it takes quite a while to get all the way to Shannon Harbour, but there are surely few more pleasurable ways of spending your time.
The Grand Canal feeders: main line and Naas Branch
Amongst the features to look out for on the virtual journey are the feeders that supplied the Grand Canal with water. The best known is the Milltown Feeder from the Pollardstown Fen, which joins the Old Barrow Line above its Old 19th Lock and supplies both the Barrow Line and the summit level of the main line. But there were many more feeders, not all of them still extant.
The feeder at Milltown
Here is a list that I have compiled from the Ordnance Survey map, checked against an old Grand Canal map and against an old edition of the Guide to the Grand Canal of Ireland (Office of Public Works 1995, but originally prepared in 1975 by Ruth Delany and Jeremy Addis). The feeders are listed from east to west. I would be glad to hear from anyone who can add to, or otherwise correct or expand, this list; please leave a Comment below.
In some cases, as with the first below, it is not clear whether there was actually a link between a nearby water body and the canal and, even if there was, whether that would count as a feeder or a drain.
Killeen Paper Mills (OSI ~1840)
- Possible outflow from Killeen Paper Mills, Fox and Geese, west of Dublin, between 7th and 8th locks
- Morrell River below 14th lock, near Devonshire Bridge
- Oldtown on the Naas/Herbertstown Branch, entering below the 3rd (Burgh’s) lock
- Rathaskea supply, entering the harbour at Naas
- Corbally Harbour at the head of the Herbertstown (Naas/Corbally) Branch
- Blackwood Feeder, drawing from the Grand Canal Company reservoir north-west of Prosperous, entering the canal west of Bonynge Bridge
- Mylerstown Supply, entering just east of Robertstown
- Milltown Feeder, fed from Pollardstown Fen and entering the Old Barrow Line upstream of the two 19th locks (one on the main line, the other on the Old Barrow Line) on the summit level near Lowtown
- Yellow River supply, entering from the north just west of Toberdaly Bridge, near Rhode
- Ballymullen supply, entering from the north just west of Daingean (Philipstown), with an overflow weir on the opposite bank
- Tullamore (Maiden) River supply, entering from the south below 29th lock at Ballycowan
- Killina mill supply, entering from the south a little further west
- Newtown supply, entering from the south west of Corcoran’s Bridge
- Derrycooley supply, entering from the south just west of 31st lock
- Lough Boora supply, entering from the south west of Pollagh.
Lough Boora Feeder (OSI ~1900)
The Grand Canal feeders: other branches
The Kilbeggan and Edenderry Branches do not seem to have had any feeders. The Ballinasloe had two, Kylemore and Ballinure. The Barrow Line (Athy Branch) had these:
White Eye supply west of Lowtown
- Milltown Feeder above the Old 19th Lock
- White Eye supply, running from the east side of the Blackwood Feeder, under the main line close to the Slate River west of Lowtown, down the side of the (new) Barrow Line and into the Barrow Line below 21st lock
- Pluckerstown supply, passing through Feighcullen and entering from the east below 22nd lock (Glenaree)
- White <illegible> supply, entering from the east above 23rd lock (Rathangan)
- Mount Prospect supply, entering from the east below 23rd lock (Rathangan)
- Mount Rice supply, entering from the east below Umeras Bridge
- Annanough supply, entering from the west just upstream of Grattan Aqueduct
- Derrybrook supply, entering from the west just downstream of Vicarstown.
The Mountmellick Branch had two feeders, one entering at Kilnacash (not far from Mountmellick) and the other at Woodbrook Bridge, south-west of Portarlington (checked against John Feehan and Fred Hamond An Ecological and Industrial Heritage Survey of the Mountmellick Canal for Laois County Council 2006).
The numbers of feeders given above match those given by Ruth Delany in The Grand Canal of Ireland (David and Charles, Newton Abbot 1973) except for the stretches from Lowtown to the Shannon and Lowtown to Athy. For each of which she says there were six feeders (but does not name them) whereas I have listed seven. However, I have listed all feeders I found mentioned; feeders may have opened and closed at different times.
I have not included any of the pumps that nowadays help to maintain levels. There is some back-pumping from the Shannon at Shannon Harbour and water is also pumped from the Liffey where the canal crosses it by the Leinster Aqueduct west of Sallins. I do not know what other pumps there are.
It should be noted that the number of feeders does not help us to arrive for a water budget for the Grand Canal, showing total inflows and losses (outflows, extraction, evaporation) . If such a thing exists, I’d like to see it: perhaps a version for trading days and another for modern times.
Here is a page about water supply to the Royal Canal.
[gc92]
Irish waterways history 
Do you have any information on the Cornmill that was situated on the Milltown feeder close to Pollardstown in the mid eighteen hundreds..
I don’t, I’m afraid. Is that the one shown here http://maps.osi.ie/publicviewer/#V2,676987,715675,11,7 on the OSI map? bjg
Yes, that the one ok.
Just in front of the chambers at the 7 lock at Killeen in Dublin water flows in to the canal I think it comes from the river camac that supplied the paper mills
Thanks for that information. The OSI maps suggest that you’re right, although it’s not the entire flow of the river (which joins the Liffey after flowing under Kingsbridge/Heuston station). The 6″ OSI map calls it the Clondalkin River and it does indeed feed the mill ponds at Killeen. There seem to be two outlets, one into the canal above the 7th lock, perhaps to allow high water levels to be drained, and the other below the lock, as you say, presumably after the fall has driven the mills.
The 25″ map calls the river the Cammock.
bjg
Hello, I am a Lynch, & so proud of it. My Grandfather came to Newark, NJ around 1890. His wife joined him later with their son. The Lynches lived over the Blackwood feeder. The Lynches operated the feeder from 1787.
There is, or was a keystone near the house of which I have a picture taken
on my visit to the remains of the canal house. My great-grandfather,
Edward, operated a canal boat. His father’s name was William. We are noted in the Waterways of Ireland by Ruth Delaney. My Grandfather Patrick,
had 5 sons & 1 daughter here in NJ. So there are quite a few decendants
of the lock keepers of the Grand Canal here in America. My Grandmother’s
name was Harris from Naas. Don’t have much information about her.
That’s very interesting, Patricia: thank you very much for telling us about it. Good to know that the Grand Canal’s history is still appreciated in the USA. I don’t know when your grandmother left Ireland, but you might find some trace of her family on the 1901 and 1911 census returns http://www.census.nationalarchives.ie/
bjg
Thank you for your information. My grandmom, Alicia Harris left Ireland in 1892, but I did find my great-grandmom in the 1901 census. Margaret
McDonald Harris lived in Robertstown.