I have a fairly short river that separates the bottom left corner of my town from the rest. So 8/10 of my villagers (plus my 3 side characters) live on the same "side" as me, although we're all actually pretty spread out, haha.
Gwen, Frank, Skye, Shep, Rosie... and that's it. Rosie being the outliar, away from all other houses (I did make sure to give her her own garden, though ^.^). My side of the river also has Town hall, it has a lot of flowers and bushes, a few public work projects. It's also the most developed part of my town.
The other side of my town has Re-Tail, The Roost, Plaza, and the Train Station/main street. Zell, Samson, Merengue, and Shari live on that side of the river.
Bonbon lives directly next to the river, Pekoe lives next to the lake, Chrissy lives near a pond and Eugene is the 2nd villager that lives near the river but not directly at it.
Also a bonus: Erik Lives near the right side of the cliffs of my town.
I don't have too many people on my side of the river. Not including myself, there are three animals living on my side of the river out of the nine animals I have in my town.