Building Access and Information Law School Campus Buildings Hours and Entrances (Fall 2022) Expand all Collapse all Jerome L. Greene Hall Main Entrance (435 W. 116th Street) Open 7 days a week: 7:00 A.M. to 11:00 P.M. Revson Plaza Entrance Monday – Friday: 8:00 A.M. to 6:00 P.M. William and June Warren ("Big Warren") Hall Main Entrance - 1125 Amsterdam Avenue Monday – Thursday: 7:00 A.M. to 10:00 P.M. Friday: 7:00 A.M. to 6:00 P.M. Saturday & Sunday: Law School CUID only William C. Warren ("Little Warren") Hall Main Entrance - 410 W. 116th Street Monday – Friday: 7:00 A.M. to 10:00 P.M., Law School CUID only All other times: Columbia Law Review students and Law School staff only Greene Annex Main Entrance - Across from East Campus Monday – Friday: 7:00 A.M. to 10:00 P.M., Law School CUID only The Greenhouse Main Entrance - 424 W. 116th Street Law School CUID only for Journal Students