The town has a total area of 16.5 square miles (42.8 km2). About13.4 sq. mi (34.6 km2) of it is land, and 3.2 sq. mi (8.2 km2) of it is water, comprising 19.21% of the town, making it a favorite location for kayakers and boaters thanks to the sheltered harbor.
The Town is also blessed with large tracts of forest, much of it conserved and crossed by hiking trails. The Proctor Wildlife Sanctuary, owned by the Audubon Society of New Hampshire, occupies 47 acres (19 ha) of woodlands northwest of the town center. Adjacent to this property is Center Harbor Woods, a 225 acres (91 ha) conservation area owned by the Lakes Region Conservation Trust and protected by a conservation easement held by the Squam Lakes Conservation Society and the town of Center Harbor. The two properties abut a third conservation property in neighboring Moultonborough, resulting in a block of protected woodland comprising nearly 400 acres (160 ha).