Pratt came into being when William B. Pratt in 1890 thought it would be a good idea to build a dam across the Agua Fria river and make a lake to hold water for the thirsty miners along the Humbug and Castle Creeks. During construction of the dam, a two room hotel, a stage station, and more were constructed. Then, a flood in 1891 destroyed the dam project but the town lived on for at least another five years as a gateway to the Bradshaw Mountains.

From the GNIS: An 1875 shows the name 'Frog Tanks' applied to this place, but later in 1890 it was renamed 'Pratt' for William B. Pratt, who had a mine here. In 1926, the name 'Lake Carl Pleasant' was approved by the post office although the name 'Camp Pleasant' had been proposed (AZ-T101).