>>1863791 (lb)
>>1863823 June 22 active shooter training at Prettyboy elementary school in Baltimore County
>>1863832
>>1864040
Looks like it's named after the nearby reservoir.
Check out the name of the nearby town (bottom left corner).
>https://en.wikipedia.org/wiki/Prettyboy_Reservoir
Prettyboy Reservoir, along with Loch Raven Reservoir that is downstream on the Gunpowder Falls, provide about 61% of the drinking water for the Baltimore Metropolitan system.
Special Department of Public Works and occasionally Baltimore City Police Officers are now patrolling all three of the metropolitan areas' watersheds
According to tradition, the lake was named after a settler's horse, Pretty Boy, who drowned in a nearby creek.