One Franklin Square is a high-rise building at 1301 K Street NW, in Downtown Washington, D.C., United States.

[1] It occupies almost the entire north side of the 1300 block of K Street NW across from Franklin Square.

The newly joined space created two 60,000-square-foot (5,600 m2) floors capable of accommodating 700 newsroom workers and software engineers.

Hines also agreed to alter the building's south-facing facade to give Post workers floor-to-ceiling windows.

[8] One Franklin Square is an important setting in the final act of the 2009 Dan Brown novel, The Lost Symbol.