1850-1851 Address Unknown, Peekskill, New York.1
1853 Address Unknown, Peekskill, New York.
1859 Address Unknown, Peekskill, New York.
Mrs. Agnes M. Armstrong was recorded in the Photographic Art-Journal (New York, New York) in the February 1853 issue. Minutes of The N. Y. State Daguerrean Association…Moved that Nichols, Benedict and Whitney, be a committee to investigate the character and good standing of the persons proposed for membership, and report at this meeting.,,
The committee of investigation reported the names of J. B. Marcus, Chenango; G. Evans, Utica; L. Gray, Oswego; E. A. Hudson, Syracuse; Mrs. Agnes M. Armstrong, Peekskill; Mrs. Marcilia W. Barnes, Salem Cross Roads; all of whom were unanimously elected…
1859 October 29. Highland Democrat. (Peekskill, New York.) October 29, 1859, Vol. XV, No. 4, P. 3.
A. M. Armstrong Informs the residents of Peekskill and vicinity that at her rooms may be found every style of Stereoscopes, With superior plates and designs by French, English and American Artists, which are offered for sale at prices lower than they can be obtained outside of New York City. Call and See!! Peekskill, June 7, 1859.
Advertisement was recorded on October 29 & November 26, 1859.
Mrs. Agnes M. Armstrong is recorded in Craig’s Daguerreian Register as Miss Armstrong in
 Craig’s Daguerreian Register listed as Miss A. M. Armstrong.