It was occupied by the defunct Croton Reservoir .
The organizers of the New York Public Library , wanting an imposing main branch , chose a central site available at the two - block section of Fifth Avenue between 40th and 42nd Streets .
New York Public Library was occupied by the defunct Croton Reservoir .
The organizers of the New York Public Library , wanting an imposing main branch , chose a central site available at the two - block section of Fifth Avenue between 40th and 42nd Streets .