If you’re slightly obsessed with Mercer Island history, as I am, you’ll want to check out this map from 1890.
I came across it again on the David Rumsey map collection, which has a number of old Northwest maps. You can zoom to many interesting features. Let’s start in North Island:
Mercerdale was the first neighborhood settled in Mercer Island. Here you can see it labeled “East Seattle,” with the large red square labeled “Caulkins Addition.” Thompson Ave, which I believe is now SE 24th St, is at the top of the main subdivision.
Mid Island was the next subdivision. The yellow is an area around the current library. It seems no coincidence that the subdivisions are about the size of our current parks: Island Crest and the three squares of Pioneer Park.
Ah, the ferries, always an interesting aspect of early Mercer Island life. Of course this was pre-bridge, so the Island must have felt much more remote then. This zoom shows the three ferries coming to Mercer Island: two to the landing dock just north of the Roanoke Inn, from Leschi and Bellevue, and a second ferry from Leschi straight into Mercerdale.