According to the latest information available, the boat ramp named Pennington County is located in South Dakota at latitude 44.06656647 and longitude -103.50121307. This boat ramp is a concrete ramp and has a width of 16 feet. It provides access to the Pactola Reservoir, a popular recreational destination for boating, fishing, and camping.

The Pactola Reservoir is a 14-mile long body of water located in the Black Hills National Forest. It is a popular spot for recreational boating, with a variety of watercraft permitted on the water, such as motorboats, sailboats, canoes, kayaks, and paddleboards. The reservoir is also known for its excellent fishing opportunities, with species such as trout, walleye, and bass.

In summary, the Pennington County boat ramp in South Dakota is a concrete ramp that provides access to the Pactola Reservoir. It has a width of 16 feet and allows various types of watercraft to be launched into the water for recreational activities such as boating and fishing.