It's to give the pitchers an advantage. Of course, these days, there isn't much of an advantage. Back in the 60s, it was raised (the mound was made higher) since the pitchers complained about the batter's advantage. Shortly thereafter, it was lowered to its present height due to the dominance of pitchers like Bob Gibson.
Pitchers mound
No
to legally play only one person can be on the pitchers mound while the game is in play
The diameter of an MLB pitcher's mound is 18 feet.
No.
YES
60'6"
second
Yes.
Measure from the front edge of the pitching rubber to the back tip of home plate.
The mound allows pitchers a much better chance of pitching within the strike zone.
More than likely a pitcher's mound is removed by smoothing the dirt out with a bulldozer.