The draw for divers at Marshall Lake is the great visibility. The lake elevation is listed at 2730', so keep that in mind for your dive profile. Max depth for the lake is lsted at 95'.
As you drive up the road you will first come to the Marshall Lake Resort which is a large camping area. The manager, Gerald, says they have about 75 numbered areas which include annual, seasonal, weekly, and nightly areas for parking RV's, campers, ect. There is water and power hook up at many of the sites, but I am not sure about sewer hookups. There is lots of room for tent camping. There are public access toilets and fee showers. There is a daily fee for parking if you are not camping. If you are staying at the resort there are 3 docks and some beach access that is included. The best way to get full details and reserve a space is to call Gerald.
Just to the East of the resort is public access to the lake. This consists of a gravel boat lanuch and a wide area for some parking. Since this is in a Washington state area you will need a Discovery Pass to park by the launch. There are signs in place stating that you need a pass. It sounds like it is ok to dive down to drop off equipment without a pass but I can not guarantee it.
As I said the draw to this lake is the nice clear water. We dove it the last weekend in June and the surface temperature was 64*F. There was a thermocline at about 25' where the temperature quickly dropped to a low of 41*F. Visability was easily 30'+ with lots of light at 25' and above. Once you dropped down below that there was sitll decent light. If you used your flashlight it really lit the area up.
Now with all the good things said, here is the bad part. There is not a lot to see. There were several old homemade anchors, few well buried fishing poles, assorted bottles and cans. In the shallows there are some logs, small ledges and some plants.
Here is the "store" where you check in.
Here are the 3 resort docks.
Here are the 3 dock pictured from the public access.
Here is the public access/launch.
What we did is have a truck haul our gear down to the water, unload, then park back up in the camping area.
There is a covered pavilion area for rent. We had a large group the day we dove so we did a BBQ. The pavilion was nice for some shaded along with several tables.
One of several old anchors.
Old fishing pole and can.
Small ledge in the shallow.
Stuff in the shallows.
Stuff in the shallows.