Norwalk Sheriff's Station deputies received a call of gunfire heard in the area of the park in the 13700 block of Adelfa Drive just after 3 a.m. Friday.
Three off-duty deputies were detained at the scene.
No one was hit by gunfire, but one of the deputies was treated for unspecified injuries at a hospital and released. That deputy was not arrested.
Deputy Judith Gonzalez, 36, was booked on suspicion of assault with a deadly weapon, and Deputy Adrienne Myers, 35, was booked on suspicion of battery, according to sheriff's Capt. Mike Parker. Bail was set at $50,000 for each.
Investigators believe the three deputies were the only people involved in the incident. It was unclear what led to the shooting.
The two arrested deputies and the injured deputy have been relieved of duty.
The investigation was ongoing.