Jacob was the youngest of Matthias Irion and Maria Magdalena Pfister's six children. He was born about 1745.
He married Barbara Leiby.
They had eight children, the two boys died in infancy: John George; John Jacob; Susannah Barbara (Mowery); Elizabeth (Mertz); Polly (Repass); Mary Magdalene (Roush); Sarah (Wittenmyer); & Margaret (Thomas).
Jacob Yerian is found in a roster for the 2nd Battalion, Lancaster Co. Militia. He is listed in Capt. Henning's Co., 6th Class, for 1782. During the Revolution, Jacob also paid Supply Tax.
Based on his estate records, Jacob died about 1814.