The current Folsom Dam, built in 1955, replaced an earlier, smaller dam that had been completed in 1893 by Horatio Gates Livermore. The earlier dam had fed the Folsom Powerhouse, generating electricity that was transmitted to Sacramento over a 22 miles (35 km)-long distribution line, the longest electrical distribution system in the world at the time. The remains of the earlier dam can be seen downstream from the Folsom Lake Crossing.
The current dam was originally authorized by Congress in 1944 as a 355,000 acre·ft (438,000 dam) flood control unit. Folsom Dam was reauthorized in 1949 as a 1,000,000 acre·ft (1,200,000 dam) multiple-purpose facility. Construction of the dam began in October 1948 and was completed in May 1956.
Some old settlements and towns were flooded when the lake was filled, including Mormon Island and Salmon Falls.
A friend and I were at an antique store and found these photos.
The first is definitely the dam being built. I am pretty sure the rest are of the lake and surrounding areas but they have not been confirmed. Comment on here if you can identify the location.
Dam being built
Possible foot bridge in front of dam.
Possible Mormon Island house demolition.
Possible Mormon Island House
Possible Mormon Island house poking out of Folsom lake.
Filling the lake.