Every now and then I see small dark snakes around the park but today I saw a rather large reddish snake so I was wondering if there are poisonous snake around the park that I should be on the look out for ?

No. It is highly unlikely to impossible to find harmful snakes in Middlesex County

Since I don't know much about snakes, I don't know whether there are any poisonous snakes in the area of the park. There are signs there in the park for all visitors and I have not seen one for any poisonous snakes.

They do have a lot of large wildlife , if you can capture a picture of the red one it would help. Anything with water around I would be careful.