others have posted his parents as William W BARTLETT b 1833 IN; d 1903 IL; m Mary Jane YOCUM b 1840 IN
of interest to me, particularly, is the post that William's parents are Jesse BARTLETT & Joanna ROSACRONCE.
Jesse is listed as b 1813/1816 in Harden Co, KY.
Both Elijah BARTLETT and George BARTLETT are in the 1810 Hardin Co, KY census.Elijah is from a BARTLETT line that has the exact same, unusual, DNA as I do - it would be fascinating to see if a male BARTLETT descendant of your Hiram had the same, unusual DNA.
Elijah m 1805 Barren Co, KY to Winnefred JETT; was in Barron Co for a few more years, then went north, crossing the Green River into Hardin Co.In 1819 Hart was formed from Hardin Co and Elijah was on the tax list in 1819 and the 1820 Hart Co census with 3 sons all born before 1810 - so that might let him out of the running to be Jesse's father.
However, George BARTLETT in Hardin Co, KY 1810 census, is probably the same in Daviess Co, KY 1820 and 1830 census - but also no sons of the right age.
Not sure if this helps - please look at World Connect and let me know if that's your Hiram.