Allegheny River Lock and Dam No. 2
Also known as: New Lock No. 2
Why it's listed
Lock and Dam No. 2 is a reinforced concrete navigation complex on the Allegheny River in Pittsburgh, built by the U.S. Army Corps of Engineers between 1932 and 1934 at the foot of the Highland Park cliffs. The lock measures 56 by 360 feet with an eleven-foot lift, and its steel miter gates and valves are operated by hydraulic pistons. A 1,393-foot fixed-crest dam, roughly 40 feet high, spans the river with no spillway. Vang Construction Company built the lock, dam and operations building. The two-story powerhouse, with its hydraulic pumps and water turbines, supplied the lock's hydraulic system. The facility replaced old Lock 2, whose chamber had become too small for standard barges and towboats by the 1920s. Its larger chamber allowed a four-barge tow to pass without breaking up. The complex is regarded as a representative example of 1930s lock construction that retains its original design and much of its equipment.
Significance in brief: The nomination argues the lock and dam are significant for their role in the Allegheny River slackwater navigation system, which allowed commercial barge and towboat traffic to reach industrial centers upriver. It also argues the facility is a representative example of lock and dam construction of 1932-1934 that retains its original appearance, function and much of its equipment.
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 00000396, listed April 21, 2000. Summary generated October 2026 (model claude-haiku-5-5, prompt v1.1-2026-10-29, confidence high).
Key facts
| Address | 7451 Lockway W, Pittsburgh |
|---|---|
| County | Allegheny County |
| Listed | April 21, 2000 |
| Reference number | 00000396 |
| Resource type | Structure |
| Period of significance | 1903-1948 |
| Architect / builder | Vang Construction Company (builder) |
| Architectural style | Late Nineteenth and Early Twentieth Century Revival |
| Criteria |
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| Areas of significance | Transportation, Maritime History, Engineering |
| Level of significance | State |
| Status (as stated in the nomination) | Lock remains in operation; the operations building was pargeted circa 1988 and some original windows have been replaced. |
| Acreage | 8.8 |
| Coordinates | 40.49108, -79.91358 (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 00000396.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q4731334
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.