1810: In a transcript of the 1810 federal census of Somerset Township, a John Hemminger household has one male and one female in the 26 to 45 age group, and one female and two males in the up to ten age group. The following image is a composite, consisting of a table from one page and a table header from another page.
1814: The Whiskers' 1983 booklet "Gunsmiths and Gunmakers of Bedford and Somerset Counties Pennsylvania 1770-1900" identifies John Hemminger as a blacksmith and a gunsmith in the borough of Somerset in 1814. On page 105 of James B. Whisker’s 1990 book “Arms Makers of Pennsylvania” John Hemminger is identified as gunsmith in the Borough of Somerset in 1814 based on a tax list.
I wonder if the basis for those statements is the following 1814 reference to a blacksmith named John Hemminger in the Somerset Borough section of the 1884 book "History of Bedford, Somerset and Fulton Counties, Pennsylvania":
The Whiskers did not include John Hemminger in their 2017 book "Gunsmiths of Somerset County, Pennsylvania".
1820: A John Hemminger appears in the Somerset Borough portion of the 1820 manuscript census records of Somerset County, Pennsylvania.
1830: A John Hemminger appears in the 1830 federal census of Somerset Borough. In the household are one male in the 30 to 40 age group, one male in the 70 to 80 age group, and one female in the 60 to 70 age group.
1840: In a transcript of the Somerset Township portion of the 1840 census records of Somerset County, Pennsylvania, a John Hemminger household has one individual in the 20 to 30 age group. This individual is too young to have been a blacksmith in 1814.
There were also Hemminger's in Bullskin Township, Fayette County, Pennsylvania, including a 1905 mill operator on Jacobs Creek. I do not know if there is a genealogical connection between the Somerset and Fayette county families.
L. Dietle