Flagler was born in Monroe County, Pennsylvania.

The evidence

• “Joseph Flagler, who is the second of nine children born to Peter B. and Mary A. (Storm) Flagler, was born in Monroe county, Pennsylvania on October 30, 1838. His parents lived on a farm in Pennsylvania, their native state, but in 1844 moved to Rock county, Wisconsin and settled on a quarter-section of unimproved laud in section 12, Janesville township, which the father purchased for $5 per acre.”

  1908-brown-rock-county/34e-biographical-5.md, Vol. 2, PDF p. 563 / book p. 1047

  Brown, William Fiske, editor. Rock County, Wisconsin: A New History of Its Cities, Villages, Towns, Citizens and Varied Interests, from the Earliest Times, Up to Date. Chicago: C. F. Cooper & Co., 1908. 2 vols. archive.org/details/rockcountywiscon01brow, archive.org/details/rockcountywiscon02brow.

  Grade A: Found on a page of one of our sources