Based on the latest information available, Forest Service Road 172-C boat ramp is located in Trigg County, Kentucky. The latitude of the boat ramp is 36.67858887, and the longitude is -88.05470276.

This boat ramp is operated by the US Forest Service and is a concrete boat ramp. It is a single-lane ramp, and the width of the ramp is not specified. However, it is wide enough to accommodate most watercraft.

This boat ramp provides access to Lake Barkley, which is a 58,000-acre reservoir located in western Kentucky. The lake is managed by the US Army Corps of Engineers and is a popular destination for boating, fishing, and other recreational activities.

The lake is open to a variety of watercraft, including motorized boats, sailboats, canoes, and kayaks. However, all boats must comply with Kentucky boating regulations and must be registered with the state before launching.

Overall, Forest Service Road 172-C boat ramp is a well-maintained and popular boat launch that provides convenient access to Lake Barkley for a variety of watercraft.