Tappan Zee
It stretches about along the boundary between Rockland and Westchester counties , downstream from Croton Point to Irvington . 
<triplet> Rockland <subj> Westchester <obj> shares border with <triplet> Westchester <subj> Rockland <obj> shares border with <triplet> Irvington <subj> Westchester <obj> located in the administrative territorial entity