Allegheny River Locka and Dam No. 5
Why it's listed
Lock and Dam No. 5 sits on the Allegheny River about one mile north of Freeport, Pennsylvania. The U.S. Army Corps of Engineers built it between 1920 and 1927 to open slackwater navigation to sand and gravel pits upstream. The lock measures 56 by 360 feet and has an 11.6-foot lift, operated by hydraulic pistons. The dam is about 22 feet high and 632 feet long, with a concrete upper section set on stone-filled timber cribs. The operations building is a two-story rubber-roofed powerhouse of about 15 by 60 feet, with a rounded upstream end reflecting a vernacular version of the Moderne style. The dam was built by Dravo Construction Company, and the lock was built with Corps labor. The facility is regarded as a representative example of lock and dam construction of its period and as part of the Allegheny River Navigation System. Its machinery, layout and design remain largely original, and the 1937 reinforcements and later alterations are documented.
Significance in brief: The nomination argues the facility is a representative example of lock and dam construction of the 1920-1927 period and an integral part of the Allegheny River slackwater navigation system, which gave commercial barge access to 72 miles of river. It states the lock and dam retain their original appearance, machinery and function and a high degree of integrity.
Machine-generated summary. This summary was generated by a language model from the official nomination document and has not been reviewed line by line by an editor. It may contain errors. Check the source document before relying on any detail. Source: nomination document (PDF) · National Archives catalog entry. NRHP reference 00000399, listed April 21, 2000. Summary generated October 2026 (model claude-haiku-5-5, prompt v1.1-2026-10-29, confidence high).
Key facts
| Address | 830 River Rd., Freeport |
|---|---|
| County | Armstrong County |
| Listed | April 21, 2000 |
| Reference number | 00000399 |
| Resource type | Structure |
| Period of significance | 1920-1948 |
| Architect / builder | Lock - Corps of Engineers; Dam - Dravo Construction Company |
| Architectural style | Moderne |
| Criteria |
|
| Areas of significance | Transportation, Maritime History, Architecture, Engineering |
| Level of significance | State |
| Status (as stated in the nomination) | In use; the dam's hydroelectric generator continues to operate and the lock remains functional. |
| Acreage | 33 |
| Coordinates | 40.68587, -79.66627 (NPS GIS) |
What listing means for this property
For a publicly owned building or structure, listing mainly matters when federal funds, permits or licences are involved: projects then go through Section 106 review so effects on the property are considered. Listing also strengthens applications for preservation grants and, for leased income-producing uses, can enable the federal rehabilitation tax credit.
General information, not legal or tax advice. Rules change; confirm with your State Historic Preservation Office or a qualified adviser.
Sources and further reading
- National Park Service, National Register of Historic Places database (snapshot May 2026), reference 00000399.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q4731337
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.