[citation needed] Echo Mountain's name is derived from the number of repetitions one's voice[4] could emit into Castle Canyon.

Boy Scout projects were made to find the "sweet spot" where the largest number of repetitions could be heard.

During the days of the Mount Lowe Railway "echophones" were set up to assist in voice projections near the best sweet spots.

On top of the mountain are the ruins of "White City", a resort along the scenic Mount Lowe Railway, which could easily be seen from the valley below.

[6] Echo Mountain can be reached by the Sam Merrill Trail located at the top of Lake Avenue, or via the fire road which extends from Millard Canyon to a point along the old right of way, which will lead to the backside of the promontory.