He was a carpenter.
"United States Census, 1900," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MSKP-3X4 : accessed 5 October 2020), Frank Gahn, Borough of Manhattan, Election District 27 New York City Ward 30, New York County, New York, United States; citing enumeration district (ED) 831, sheet 1B, family 23, NARA microfilm publication T623 (Washington, D.C.: National Archives and Records Administration, 1972.); FHL microfilm 1,241,118.
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