In the late 1800's, the Squak Valley was a center of the logging
industry. Lake Sammamish, then known as Squak Lake, provided an
ideal route for bulk cargo to travel to Seattle; logs, lumber, and
millwork were floated up the lake, along the Sammamish river, down
through Lake Washington (nee Duwamish Lake) into the Black River,
then out the Duwamish River to Seattle.
Simon Donnelly was one of the men capitalizing on this industry.
Donnelly built a sawmill on the water near where waypoint 1 of this
cache is today. Logs brought down Issaquah (Squak) creek were
hauled up at the inlet here, sawed, then shipped off to markets in
the city. The mill attracted enough people to the area to justify a
Post Office (with Donnelly the Postmaster), and on 5 February 1885
the mill town of Donnelly was born.
When the Seattle, Lake Shore and Eastern Railway built tracks
along the eastern shore of the lake in 1889, the economics of
shipping changed drastically. It became far cheaper and quicker to
transport cargo via the railroad, and mills like Donnelly Mill had
to adapt or die. High demand for lumber after the Great Seattle
Fire that same year accelerated this process.
(The coming of the railroad also sparked a boom in coal mining.
Daniel Hunt Gilman, owner of the major coal mines in the area, was
instrumental in establishing the railroad, and the mining town that
was to become Issaquah incorporated as Gilman in 1892.)
Bypassed by the railroad, Donnelly Mill sold to the Allen &
Nelson Mill Co. and in 1889 relocated next to the new tracks across
the lake. The Post Office went with it, and the town of Donnelly
faded away into memory.
Today, nothing is left of this once prosperous, albeit
short-lived town. The land remains unincorporated in King County,
although Issaquah has recently agreed to annex this area. Even the
railway that caused Donnelly's demise has faded away, transformed
into the newly opened East Lake Sammamish Trail.
Much of this information was derived from articles at
http://www.historylink.org/