First off, I'm no relation so I don't have any other information than what I am posting.I thought I'd take a stab and see what I could come up with.I hope I can add something new and not just repeats of what you might already have!
I was able to find Jefferson on the 1910 Vigo Twp., Knox Co. census.He was living in the town of Sandborn with his wife.I also found him on the 1870 Vigo Twp., Knox Co. Census.In 1850, he was living in Cass Twp., Greene Co., IN.I just put his name in the search box to find these at ancesty.com.He didn't come up for the 1880 or 1860 census' so his name was probably mispelled.
I found his marriage date to Sarah Ann Hammersly to be 8 Nov 1849 in Daviess Co.
And, on the 1830 Knox Co., IN census there are 5 Jarrell's listed on the same page.The name was spelled Jerrel.Three Charles, one William and a Jefferson who would have been between 20-30 years of age.Just thought that was interesting.
Oh, I found Jefferson's Civil War data on ancestry too.It listed his residence as Newberry which is in Greene Co. Here is the record:
American Civil War Soldiers Record
Name: Jefferson Jarrell , Residence: Newberry, Indiana Enlistment Date: 13 August 1862 Distinguished Service: DISTINGUISHED SERVICE Side Served: Union State Served: Indiana Unit Numbers: 636 636 Service Record: Wounded Enlisted as a Private on 13 August 1862 Enlisted in Company K, 80th Infantry Regiment Indiana on 13 August 1862. Transferred Company K, 80th Infantry Regiment Indiana on 24 December 1863 Transfered in on 24 December 1863
I don't know if you've been here but the 80th Indiana has a great website.My 3rd great-grandfather was also in the 80th only a different company. See it here:www.80thindiana.com