Thomas Mill Covered Bridge

About Thomas Mill Covered Bridge

The Thomas Mill Covered Bridge is a historic 86.5-foot Howe truss bridge spanning Wissahickon Creek in Wissahickon Valley Park in Northwest Philadelphia. This remarkable structure holds the distinction of being the only remaining covered bridge in Philadelphia and the only covered bridge in any major American city. Listed on the National Register of Historic Places in 1980 and a contributing property of the Chestnut Hill Historic District, this bridge offers visitors an unexpected rural escape within one of America's largest cities.

History of Thomas Mill Covered Bridge

The history of the Thomas Mill Covered Bridge is intertwined with the industrial heritage of the Wissahickon Valley. A bridge crossing at this location may date back to 1737, serving the many mills that once operated along Wissahickon Creek. The current covered structure was built in 1855, replacing an earlier open-span crossing that served nearby Thomas Mill, one of the many gristmills that powered Philadelphia's early industrial economy. The Magargee family operated the Upper Magargee Mill at this location, which began as a gristmill in the 1760s shipping 165,000 barrels of flour annually before converting to a paper mill in the 1850s. The bridge was extensively restored in 1939 by the Works Progress Administration during the Great Depression, providing jobs while preserving this historic landmark. When automobiles were banned from Forbidden Drive in the 1920s, the bridge was spared from demolition, earning its serene setting. A $420,000 rehabilitation in 1999 funded by the Fairmount Park Commission ensured the bridge would survive for future generations.

Architecture and Design

The Thomas Mill Covered Bridge features a Howe truss design, patented by Massachusetts constructor William Howe in 1840. This design uses vertical iron posts and wooden diagonal braces to create a strong and efficient structure. The bridge measures 86.5 feet long and 18.66 feet wide, featuring traditional wooden planks set in a crosswise pattern and stone abutments at either end that support the structure. The Howe truss was popular in the mid-19th century for its combination of strength and simplicity, and Thomas Mill is one of only five remaining Howe truss covered bridges in Pennsylvania. The bridge's distinctive red exterior has made it an iconic Philadelphia landmark, its vibrant color contrasting beautifully with the surrounding greenery in summer and snow in winter.

Visiting Thomas Mill Covered Bridge

Visiting the Thomas Mill Covered Bridge requires a pleasant walk of about half a mile through Wissahickon Valley Park, as no roads lead directly to the bridge. The bridge is located at coordinates 40.071889, -75.225632 and is accessible year-round from dawn to dusk. Two main approaches are available: from the Chestnut Hill side via a parking area across from 440 W Chestnut Hill Avenue, or from the West Bells Mill Road parking area at coordinates 40.078250, -75.227564. Those using public transit can take the Chestnut Hill West commuter train to Highland Station. The bridge connects Forbidden Drive to the Orange Trail and is open to pedestrians, bicycles, and horses. The surrounding 1,800-acre Wissahickon Valley Park offers extensive hiking trails, the Tedyuscung Statue, Houston Meadow, Valley Green Inn for dining, and the stunning Wissahickon Gorge. The park setting feels remarkably remote despite being within Philadelphia's city limits, offering a true escape into nature and history.