Bethlehem Steel Lehigh Plant Mill #2 Annex, also known as Merchant Mill No. 2 and the Johnson Machinery Building, is part of the historic steel mill located in Bethlehem in Northampton County and the Lehigh Valley region of eastern Pennsylvania. It is a large, square, two-story brick industrial building.
The Mill #2 Annex was built between 1940 and 1942, by the Bethlehem Steel Corporation.
It was originally designed and built as a surface preparation and finishing mill for the Alloy and Tool Steel Division at Bethlehem Steel's Lehigh Plant in Bethlehem.
The Mill No. 2 Annex was added to the National Register of Historic Places in 2004.
The building has since been renovated and currently contains condominiums, two commercial properties, and a parking garage.