U. S. Post Office

The Gloucester City Post Office was created as the industrial expansion into Gloucester took place in the 1840's.  As David Sands Brown brought business, 

In 1845 the appointment of a Post Master was something the President of the United States did and the Post Master served at the pleasure of the President which meant when the President change, it was likely the local Poster Master would so after be replaced.

Todays Post Office was built in 1935 as part of the U.S. Government W.P.A. program.

The NEW JERSEY POSTAL HISTORY SOCIETY (online) provides more information about the history of the Gloucester City Post Office and the Post Masters:

https://www.njpostalhistory.org/media/archive/118-may96njph.pdf