Piney Point Lighthouse is the oldest lighthouse on the Potomac, constructed in 1836 by prolific lighthouse builder John Donahoo. The tower was the first of eleven lighthouses to be built along the river, and it is one of only three historic lighthouses that remain standing today. Today, the lighthouse and grounds serve as a museum.

piney point
Piney Point Lighthouse Museum. Photos courtesy of St. Mary’s County Museum Division

The St. Mary’s County Museum Division, which oversees several museums and historic sites throughout the county, has added a brand-new exhibit to the Piney Point Lighthouse Museum, a replica Fifth Order Fresnel Lens.

This intricate and unique lens, an exact reproduction of the original apparatus that once lit Piney Point Lighthouse’s tower and guided mariners to safety on the Potomac, was purchased from, created, and installed by Florida-based company Artworks Florida Classic Fresnel Lenses, LLC, after several years of fundraising by the Friends of St. Clement’s Island and Piney Point Museums. The reproduction lens is a complex and intricate device and costs around $30,000 to produce.

Though Piney Point Lighthouse once utilized a Fifth Order Fresnel Lens when in operation, during the many years since being decommissioned the lens was lost to history. When developing the recently installed exhibits at Piney Point Lighthouse Museum, the St. Mary’s County Museum Division and the Friends of St. Clement’s Island and Piney Point Museums wanted to add something exciting as the focal point of the new displays. Bringing back an exact replica of Piney Point’s once-used Fresnel Lens was chosen as the perfect centerpiece. Future plans for the exhibition include exhibit panels and a “Learn About the Lens” program for visitors.

piney point
The replica Fifth Order Fresnel Lens.

Dan Spinella, owner of Artworks Florida Classic Fresnel Lenses, installed the lens February 20, 2021. The company, established in 1992, custom designs and manufactures historic full-scale reproduction Fresnel lenses that were used to illuminate lighthouses in the 1800s. Along with their full reproduction work, they also reproduce components used in the restoration of original Fresnel lenses. These lenses are used in interpretive exhibits at museums as well as private aids to navigation in many lighthouses around the United States.

Invented and developed by French physicist Augustin Fresnel in the early 1800s, Fresnel lenses revolutionized the way lighthouses illuminated the waterways of the world. This ingenious contraption utilized a complex system of lenses, mirrors, and panels rotated by a weighted clockwork mechanism with gears and cables like a grandfather clock. This allowed the lens to rotate at specific speeds depending on the lighthouse’s lighting requirements. This allowed it to radiate much more light in all directions, something previous lighting methods did not allow. Because of the design, these lenses are not only engineering marvels, but also incredible works of art.

For more information about this exhibit or how to visit and take a tour of Piney Point Lighthouse Museum, please call (301) 994-1471 or visit

To read about other lighthouses on the Bay, check out Chesapeake Bay Lighthouses.