"DeShon" is an Anglicized version of the French "des champs" (which is pronounced remarkably similar). The literal translation is "from the fields". It is a old colloquialism referring to somebody who works in the fields, i.e., a farmer.
As the early farmers left France for England and America, the spelling took on a variety of local flavors, depending on the location. In America, it's not unusual to see it spelled "Dishon", "Deshawn", "Deshong", and "Deshone".
My earliest American ancestors changed the spelling to the phonetic "Dishon". Within couple of generations, it had changed to "DeShon", but different branches of the family adopted slight variations on that.
It's not unusual for census takers to guess the spelling of the interviewee. I have found census records of my grandfather that spelled it "Dishon", even though there is no evidence he ever used that spelling himself. In old cursive writing, it is difficult to distinguish a lower-case "e" from an "i", so the spelling could be misread even with the best of intentions.
Even if you don't spell it exactly like I do, there's a good chance that if the pronunciation of your last name is similar, we have a common French ancestry.
In recent years, "Deshon" or "Deshawn" has become a common first name, especially in the African-American community. When used as a first name, it has a different etymology. It is probably a variant of "Sean", the Irish version of "John". It's not uncommon to add a prefix of "de", "da", or "la" to create a contemporary, urban-sounding name.