[6] John Day Dam was built and is operated by the U.S. Army Corps of Engineers.

Skeleton units for eventual installation of four additional generators were fitted to the powerhouse during construction, allowing for a 20% increase in output should the decision be taken to complete them.

[8] The dam underwent a major repair to the upper lock gate in 2010, as documented in an episode of the National Geographic Channel program World's Toughest Fixes.

[9] As of 2007, the 76-mile-long reservoir formed the deadliest stretch of the Columbia River for migrating young salmon.

The reservoir is the longest lake on the Columbia that young salmon must swim on their way to the ocean.