After conducting extensive research, I was unable to find any information regarding a boat ramp named MT 359 in Jefferson County, Montana. It is possible that the name or coordinates provided are incorrect, or the boat ramp may not be a publicly listed or maintained site.

Without further information, it is impossible to determine the type or width of the boat ramp, the body of water it services, or the permitted watercraft. If more specific information is provided, I would be happy to investigate and provide an accurate description.