The Grant Mills Bridge, officially the Millbrook Bridge, is a wooden covered bridge over in Hardenburgh, New York, United States. It is one of 29 covered bridges in the state. It was built in 1902 by a pair of local builders in the lattice truss design perfected early in the previous century by Ithiel Town. It was taken out of service in 1964 when Mill Brook Road was relocated a short distance to the south, but remains in excellent condition and is open to foot traffic. In 1999, it was listed on the National Register of Historic Places.