FEMA rejected the request last month, saying the damage was not severe enough. It found that 80 percent of homeowners affected were covered by insurance and said those who weren't could work with local and state governments to get assistance.
But Christie announced Thursday that the state had filed an appeal.
Christie initially requested aid for Passaic, Bergen, Essex and Morris counties after rain-swollen rivers flooded streets and homes. In his appeal letter sent to President Barack Obama, the governor said he's also seeking aid for Warren County.