Summary: my brick wall boils down to three individuals I've found that I'd like to combine into one, but all three are hard to learn anything about. All were born around 1878 according to what little information I have.
Primarily, I've been looking for an inventor and railroad engineer named H. C. Hornback for nine years. He was an obscure individual who lived on trains, in hotels and boarding houses. I haven't found him in any census. I learned about him from a couple of Portland, Oregon newspaper articles from Dec. 1909. He said he'd lived in Colorado from about 1894 to 1909.
In the course of the search I've located parents for a deceased person who was adopted and therefore whose parents were unknown till I found them. His father was named Henry Clay Hornback and he is also hard to find. He died May 3, 1915 in San Francisco, California. He was born about 1878 in Kentucky or Australia (his widow said both back in 1915 according to two different primary documents). Her maiden name was Mary Elizabeth "Bessie" Cullen.
I also think that Clay Hornback of Rocky Ford, Otero County, Colorado is the same person. His father was Solomon Henry Hornback who supposedly came from Nicholas County, Kentucky and who definitely married his wife Eliza P. Edmonston in Mississippi County, Missouri in 1874. I can't find this family anywhere in the 1880 census so I wonder if they were in Australia for a while.
Clay was arrested in 1896 for stealing a bicycle. I found an H. C. Hornback, prisoner number 4084, at the Canon City, Colorado penitentiary but that's all I know about that. Links below describe archived data that may or may not be online at www.colorado.gov. Due to a new Colorado law limiting access to the colorado.gov website, since I live in Asia I can't open the colorado.gov site to see what the procedure is for getting the images if they are not online. The Colorado genealogy site linked below says the images are online or seems to imply it.
I'm an amateur genealogist. I've got 484 files on this family and found nothing on these three men (or two, or one) except a few newspaper articles, city directories from Portland, Oregon, and death report from San Francisco, California. It's at familysearch.org. The Henry Clay Hornback who died in San Francisco was married to Mary Elizabeth "Bessie" Cullen and she is easy to find but he isn't. I have the birth certificate of their child, who is deceased. The two different names he had (due to being adopted) are irrelevant to this discussion as his father died before he was born and he didn't know anything about him except for what was on his birth certificate and he was not raised by his mother.
https://www.colorado.gov/pacific/archives/penitentiary-records is not accessible from where I live in Asia. https://coloradogenealogy.com/history/prisoner-records-available-at-the-colorado-state-archives.htm describes what should be found there.