The Arboretum is located on the outskirts of Stoneybrook, Connecticut.
It is described as having a tree-lined, semi-circlular driveway that leads to a gigantic, three-story brick house with huge windows trimmed in white.
The front entrance is formal looking with broad steps leading to a small porch with an arched roof & wide white columns on either side.
An old-fashioned greenhouse is built onto the left wing. It is approached through an empty living room and the upstairs is closed off. It is described as being full of plants on the shelves, on the floor and climbing up trellises.
A big wrought iron gate leads to the house & the grounds.
The curator of the Arboretum is Mrs. Goldsmith (who leaves at 6:00 p.m.). When the Arboretum was about to be shut down, the Baby-Sitters Club help them out.
A woman named Mrs. VanderBellen decides not to buy the land, but then she later donates money.