| Pennyfield Lock | |
|---|---|
 Pennyfield Lock and lock house in 2020 | |
 | |
| 39°03′13″N 77°17′20″W / 39.05372°N 77.28887°W | |
| Waterway | Chesapeake and Ohio Canal |
| Country | USA |
| State | Maryland |
| County | Montgomery |
| Operation | Defunct |
| Towpath milemarker 19.7 | |
The Pennyfield Lock (Lock #22) and lockhouse are part of the 184.5-mile (296.9 km) Chesapeake and Ohio Canal (a.k.a. C&O Canal) that operated in the United States along the Potomac River from the 1830s through 1923. The lock, located at towpath mile-marker 19.7, is near River Road in Montgomery County, Maryland. The original lock house was built in 1830, and its lock was completed in 1831.
The name "Pennyfield" is a misspelling of the family name of long-time lock keepers George and Charles Pennifield. George, and then his son Charlie, operated the lock from the 1880s until it was permanently closed. George was an avid fisherman, and once hosted President Grover Cleveland for several days of fishing near the lock.
Today, the lock and restored lock house are part of the Chesapeake and Ohio Canal National Historical Park. The area is a favorite of bird watchers, and the Pennyfield Lock Neighborhood Conservation Area and Dierssen Wildlife Management Area are both accessible using the lock's towpath.