My definition of Lower Edmonton ties in with the N9 postal area. That is how I have known it all my life so I am sticking with it. It is my site so I get to draw the lines and I also get to move them when I feel like it. I understand the London postal areas were an invention of the Post Office in the mid-19th century for their own convenience in making deliveries and predate even the London County Council by many decades. I don't know to what extent they have been refined since. They always have been and remain a law unto themselves but I am happy enough with N9 as being pretty reasonable.
Using the N9 area probably isn't too bad a definition and it is perhaps the only clear cut one it has ever had. The Edmonton Hundred of Middlesex, the Parish of Edmonton, the Local Boards pre- and post- separation from Southgate, the Urban District Council and the municipal Borough had their boundaries but Lower Edmonton was a village and then a town within them and its boundaries were natural ones like surrounding green space.
I grew up in a road where the postcode was N9 but the street furniture changed part way along which suggested to me that the administrative border with Ponders End may have gone straight through it. I always found it slightly curious. There has at least long been a well defined boundary of Edmonton to the north though, and this can usefully be employed to define the limit of Lower Edmonton too.
To the south the border of N9 is along Brettenham Road, Park Road, Park Lane and Westerham Avenue. Whether that really reflects the meeting point of expansion south and north I don't know but it must be about right.
I don't know if those living between Church Street, Bury Street West and the Great Cambridge Road (A10) really consider themselves in Lower Edmonton, or if they consider they are in Bush Hill Park or Winchmore Hill. Certainly it does have a 'feel' more like the latter places though it was part of the borough of Edmonton. Part of the area could reasonably call itself Bury Street really as there was a hamlet of that name roughly around where the Bury Street / Cambridge Road junction is now. The A10 forms something of a natural divide (though north of Bury Street the Southbury branch of the railway is the N9 boundary) but is a purely 20th century invention. Church Street and Bury Street West are much older roads. The area generally gets bundled in with 'Edmonton' in literature and as the area has an N9 postcode I treat it as Lower Edmonton.
Richard Burton contributed these photos of a boundary stone. The markings are 'Borough Of Edmonton 1937' on one side and 'Urban Borough Of Enfield' and a date on the other (or something similar). I managed to guess the rough location. Can you do the same? Answer at the foot of the page.
If you pass St Stephens Church on the junction of Park Avenue and Village Road you will see a signpost belonging to the Edmonton Urban District Council showing that this area was still part of Edmonton even after the split with Southgate, though I've always thought of it as very much 'belonging' to Enfield. I guess this is a reflection of the areas of Bush Hill Park west of the railway line having more upmarket housing. North-east of the railway line is a little more down market and has more in common with parts of Lower Edmonton though not necessarily the parts next to it! The northern boundary of Edmonton runs north of St Stephens church and Bush Hill Park station and probably runs roughly where Alberta Road is (I believe Saddlers Mill Stream marks the boundary). The western boundary of the UDC ran along Bush Hill which was the old main road to Enfield continuing on from Green Lanes and indeed marked as Green Lanes itself on old maps (RIdge Avenue is an early 20th Century road created to bypass the hill). It then ran along Firs Lane. Although I do make some mention of it in a historical context on the site, I exclude this area from my definition of Lower Edmonton simply on the lack of the N9 postcode in the same way I pull in the Bury Street area. This is what I mean about the N9 postcode largely having defined Lower Edmonton.
How did you get on with the mystery boundary stone? Well given the markings we know it must refer to the old Borough Of Edmonton and that had Southgate on the west side so it had to be somewhere to the north. I figured that given the green space and the footpath that it would have to be on the north-west corner in the Bush Hill Park golf club sort of area and indeed it is. The boundary stone is beside Carrs Lane, the path running from Bush Hill to Old Park Avenue. The old parish and then borough boundaries ran along the path for a few hundred yards before swinging east to join up with Saddlers Mill Stream. I'd be interested to know if there are any other such stones around.