The group fears the impact will be felt all the way to Lake Washington, as runoff from the cleared area overwhelms a stream and culverts that drain the area.
The stream crossing is the only way Helen Farrington of Issaquah can reach her home. The culvert there was recently rebuilt to withstand high waters after years of flooding.
Residents spent $100,000 on the culvert project, but now there's a new concern all that work could be washed away.
"It's panicking - it makes me panic," says Farrington.
An Eatonville logging company wants to clear-cut 216 acres of trees on the mountain above the stream.
"Once you've taken away all that foliage cover, that sponge - all of that water all of a sudden comes down, overwhelms the natural drainage system," says Farrington.
Pink ribbons mark the areas to be logged on Squak Mountain if Erickson Logging secures a state permit.
Local resident Dave Kappler is leading the Save Squak Mountain group. He's concerned about hiking access and protection of the environment.
"Every time I go there it energizes me to see some of the big trees that are on this property," he says.
Some residents opposed to the logging company's proposal are hoping county and state officials will purchase the land.
"If King County working with other (jurisdictions) - such as the state and other funds - could purchase it unlogged, (that) would be the ideal situation," says Kappler. "We could end up with some great trailhead on Squak Mountain, which we need."
"It's clear, it's beautiful - you can see looking into it that it's healthy," says Farrington.
Residents also fear clear-cutting would cause silt to fill the local creek where salmon spawn. The fish returned here after the culvert was rebuilt.
Farrington now wants the state Department of Natural Resources to conduct an environmental review.
"If this gets washed out again, I'm not sure what we would do," she says. "I'm not sure how we would handle it because we would be back to square zero."
Erickson Logging did not respond to KOMO News' request for comment. The company has not submitted a forest practices application.