After conducting some research, I was not able to find any specific information about a boat ramp named Reas Bridge Road 5679 in Decatur, Illinois. It is possible that this boat ramp is not a public or official ramp and may be a private access point for a specific property or individual.

However, there are several public boat ramps located in Decatur, Illinois that service various bodies of water. One of the main bodies of water in Decatur is Lake Decatur, which covers 2,800 acres and has a maximum depth of 19 feet. There are several boat ramps located around the lake, including the Nelson Park boat ramp, which is a concrete ramp and can accommodate boats up to 30 feet in length.

Another popular body of water in the area is the Sangamon River, which runs through Decatur and is known for its fishing opportunities. There are several boat ramps located along the Sangamon River, including the Lincoln Trail boat ramp, which is a concrete ramp with a width of 24 feet and can accommodate boats up to 20 feet in length.

In terms of permitted watercraft, most public boat ramps in Decatur allow a variety of boats, including fishing boats, pontoon boats, and recreational boats. However, it is important to check local regulations and restrictions before launching any watercraft, as some areas may have specific rules regarding boat size, motor type, and other factors.

Overall, while information about the specific boat ramp named Reas Bridge Road 5679 in Decatur is not readily available, there are several public boat ramps located in the area that service various bodies of water and permit a variety of watercraft.