According to the Mason County Parks and Recreation website, the US 101 boat ramp is a concrete ramp with a single lane, located on the west side of US Highway 101, in the town of Shelton, Washington. The width of the ramp is not specified on the website.

This boat ramp services the Oakland Bay, which is a tidal bay of the Puget Sound. The website states that the bay is suitable for small boats and kayaks. However, it also warns that the bay is subject to strong tidal currents, which can be dangerous for inexperienced boaters.

In terms of the types of craft permitted on the water, the website specifies that motorized boats are allowed, but there are restrictions on their use. Boats with a motor larger than 10 horsepower are not permitted, and there is a no-wake zone in effect within 500 feet of the shoreline.

Overall, the US 101 Mason County boat ramp appears to be a simple concrete ramp suitable for small boats and kayaks, located on a tidal bay that is subject to strong currents. Motorized boats are allowed, but there are restrictions on their use.