Yes, vehicles can be left overnight to camp on the lake. The area is day use only for those staying at the swim area/frisbee golf/ picnic areas. Lots of kids used to come up at night to smoke weed and "make out" etc. So Army Corps made it day use only for those areas around Barclay Bay and Turner Gulch. Make sure you lock your vehicle if left overnight. Lots of stolen items from unlocked cars. Enjoy.
I parked overnight last year and had no issues. Just make sure you have both days paid for in advance and proper information displayed on dash of the vehicle.
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