After conducting research, it seems that there isn't any specific boat ramp named Grayson County in Texas. However, Grayson County is an actual county in Texas, located in the northern part of the state. It is home to several large lakes, including Lake Texoma, which is a popular spot for boating, fishing, and other water activities.

Lake Texoma is a massive reservoir on the Red River, bordered by Texas and Oklahoma. It covers an area of over 89,000 acres and has a maximum depth of around 100 feet. There are several boat ramps located around the lake, allowing boaters easy access to the water.

One of the largest and most popular boat ramps on Lake Texoma is the Highport Marina Boat Ramp, located on the south side of the lake in Pottsboro, Texas. This boat ramp is approximately 60 feet wide and can accommodate a wide range of watercraft, from small fishing boats to larger cabin cruisers.

According to the latest information from the Texas Parks and Wildlife Department, all types of watercraft are permitted on Lake Texoma, including personal watercraft, sailboats, and motorboats. However, there are certain rules and regulations that boaters must follow, including speed limits, safety requirements, and mandatory equipment. It is always recommended to check with local authorities for the latest rules and regulations before taking to the water.