Unfortunately, the information provided in the question is incorrect. White Potato Lake is not located in Illinois, but rather in Wisconsin. Therefore, it is unclear which boat ramp is being referred to.

However, based on research, there is a boat ramp located on White Potato Lake in Wisconsin. According to the Wisconsin Department of Natural Resources, the boat ramp is located on the south side of the lake and is open to the public. It is described as a concrete ramp with a moderate slope and can accommodate small to medium-sized watercraft.

There is no information available on the width of the boat ramp. However, the Wisconsin Department of Natural Resources states that the lake is 102 acres in size with a maximum depth of 20 feet. Only electric motors are allowed on the lake, so all watercraft must be electric or non-motorized.

In conclusion, the boat ramp at White Potato Lake in Wisconsin is a concrete ramp with a moderate slope. It services White Potato Lake, which is a 102-acre lake that only allows electric and non-motorized watercraft.