[1] Capitol Park is located on the western bank of the Kennebec River, from which it is separated by a former railroad right-of-way.

It is about 20 acres (8.1 ha) in size, and roughly rectangular in shape, bounded by Capitol, State, and Union Streets.

As part of the landscaping of the state house grounds, Charles Bulfinch articulated a design for the park that established a series of terraces descending to the river.

All of this landscaping was lost when the area was used as a staging ground for the state's troops in the American Civil War.

Work on the park to implement this design was overseen by Portland landscape architect Carl Rust Parker.