Goddard Mansion's ruins can be found inside the park. It was designed by Charles Alexander and completed in 1859. Originally built for John Goddard, a local businessman and volunteer army colonel during the Civil War, the army purchased the building in 1900 and converted it to quarters for noncommissioned officers. By the time Fort Williams was purchased by Cape Elizabeth, the mansion was in serious disrepair. In 1981 the Town MAnager determined that the building must be restored, so the local fire department burned the interior of the house to remove dangerous debris. The building became open to the public until 2009 when the building was declared unsafe.
The park also includes an arboretum. It began in 2007 by several graduates of the University of Master Gardner Program who were concerned about the negative impact of invasive plants on the grounds. After getting the support of local business people and horticulturists from the university, a plan was presented to the town of Cape Elizabeth. Over 1,000 volunteers came to support the plan, many having gardening experience. Two landscapes, Cliffside and Lighthouse View have been completed, and a Children's Garden is in the process of being developed.
The Portland Head Light is also located in the park. A rock near the lighthouse commemorates the wreck of Annie C. Maguire. On December 24, 1886, the mast of the boat hit the ledge of the lighthouse and the boat became stuck. The lighthouse keeper, Joshua Strout, with the help of townspeople, made a ladder that could stretch from the shore to the ship. The eleven people on the ship made it to the shore safely. However, the reason for the wreck was never known, as the crew claimed to clearly see the lighthouse and have no visibility problems.