The largest body of water in Middlesex ison the eastern edge of the town. There is a Wrightville Beach Recreation Area located there.
The southern border of Middlesex is drawn on the Winooski River, first called Onion and sometimes French River by the colonists, separating the town from its neighbor, Moretown. Great Brook is another waterway in Middlesex, however considerably shorter. It's name is probably sarcastic because it is only five miles long. Graves Brook, nearby, was named for a family whose descendents still live in the area. Herrick, Martins, and Patterson Brooks were also named for former townspeople.
The most prominent peaks in Middlesex are Chases, Densmore, Burnt, and White Rock Mountains. Dumpling Hill and East Hill are also named features. The peak of Mount Hunger, the tallest mountain in the Worcester Range, is located just north of Middlesex in Worcester.
In 1927 a major storm caused floods across Vermont. Middlesex was not spared.
A "rocking stone" was located near Middlesex Center. It was a rock of several tons perched on top of a small cliff, which was easily rocked back and forth if a person touched it.