Actually, in my experience, there are some pretty large swaths of stream that are on private property. Heck, the Boy Scout camp owns pretty much half of the lower canyon.
And I know that towards the upper part of the canyon (above the gate) there are other significant stretches that run over private property.
And I haven't even mentioned the ponds around Log Haven - all posted no trespassing.
If you're looking for a slow pond, there is a pond just above Log Haven (above the Porter Fork turnoff) that is a little slower. Not particularly deep, but slow - and there's a boardwalk surrounding that whole area.
Honestly, I've fished Millcreek pretty extensively for years and that pond has never done much for me. I tend to avoid it in the summer because it gets pretty crowded (and that's what I'm trying to avoid in Millcreek) but the streams have consistently produced fish. Not exactly lunkers, but still fun.
I've heard different things about the accuracy of this map, but if you zoom in on Millcreek, you can see the different stretches of public and private land:
http://wildlife.utah.gov/maps/stream_access/
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