City Parks cops who patrolled Battery Park City for decades are getting swapped for a private security firm.

The Battery Park City Authority board voted on Oct. 27 to give Pennsylvania-based AlliedBarton a $2.1 million contract to police the lower Manhattan neighborhood’s 38 acres.

Board members, who are appointed by Gov. Cuomo, argued they will save $400,000 by not renewing its $2.5 million agreement with the city.