The state Office of Fishing and Boating Access has set limitations to parking in state public access boat ramps.
Here are the numbers for our Manchaug Pond:
Total Trailer Spaces: 28
Maximum July 1 through August 31: 14
Maximum September 1 through June 30: 22
View today from the ramp looking north to the lake 
and south to Holt Road.
http://www.mass.gov/dfwele/pab/fba_parking.htm