AT&T Mobility, LLC is proposing to modify the existing 133-foot-tall (136-foot overall height) building wireless telecommunications facility located at 3900 City Line Avenue, Philadelphia, Philadelphia County, PA 19131 (N40° 00' 30.1" and W75° 12’ 21.3”). AT&T Mobility, LLC invites comments from any interested party on the impact the proposed undertaking may have on any districts, sites, buildings, structures, or objects significant in American history, archaeology, engineering, or culture that are listed or determined eligible for listing in the National Register of Historic Places under National Historic Preservation Act Section 106. Parties interested in commenting on this Federal undertaking or with questions on the proposed facility should contact Eocene at 8951 Windsor Parkway, Johnston, IA 50131 or call 515-473-6256 and reference project #NE 1250/JC. Comments must be received within 30 days of the date of this notice.