Lake Carnegie is a reservoir that is formed from a dam on the Millstone River, in the far northeastern corner of Princeton, Mercer County, New Jersey. The Delaware and Raritan Canal and its associated tow path are situated along the eastern shore of the lake. Noted businessman and philanthropist Andrew Carnegie donated the lake to Princeton University. In 1990, the Lake Carnegie Historic District was listed on the National Register of Historic Places.
The lake is used by the university's rowing team, and is home to the US Olympic rowing team.