Good ! You seem (easily) far wiser than insisting on "Lethbridge, Alaska" even though the term was "a Lethbridge in Alaska".
Note that rivers probably dont count, as they are not fixed features...like statues, hotels, municipal buildings, towns, cities, etc.
Lakes and ponds are good.
Is there a lake lethbridge on Baffin island?
or
lethbridge lake
.....?
The word Lethe seems to have nothing to do in terms of origin with the term Leth has in Lethbridge which seems to be Celtic and not Greek.
Aside from the fact Lethbridge originated has a family name in Devon England and Lethe is the name of a river in the Greek underworld.
I checked the Canadian Geographical Names Database (CGNDB)
http://www4.nrcan.gc.ca/search-place-names/search according to it there is Lethbridge Lakes, Two very small lakes on Baffin Island next to each other. Named in 1951.
In Saskatchewan there is a Lethbridge Lake named in 2004. part of it is in the Northwest Territories.
There is a Lethbridge Road in the Province of NewFoundland and Labrador near the village of Lethbridge.
There is a Canadian Armed Forces training range called Lethbridge near Lethbridge Alberta.
There is a small lake called Lethbridge in Manitoba named in 2020.
All of those names seem to be allusions to Lethbridge Alberta or the Lethbridge family.
I find it interesting that it was very easy to check all this out and also that many of the names are late and postdate, with the possible exception of Lethbridge in New Foundland, the founding of Lethbridge Alberta.
I also find it interesting that in the USA the name Lethbridge is totally absent has a name of a habitation or a geographical feature which did quite surprise me.