Wow holy cow! I didn’t know this was online! That’s incredible, and it goes back to 1866
http://chroniclingamerica.loc.gov/lccn/sn83030214/1866-04-10/ed-1/seq-1/
Who saved these papers?
Way back in the day both the actual newspapers and public libraries would save full runs of their papers in cellars or storerooms as a sort of manual archive. Later with the development of microfilm most of the surviving papers were copied onto that medium. Special efforts were made to collect and microfilm the remaining papers and copies were sent to some deep mountain special storage. I am guessing this was to preserve records in the event someone pushed the button and blew up the world.
Now we are getting more and more old papers digitized and posted online. There is a separate run of the Tribune from 1842-1866 which can be found here...
http://chroniclingamerica.loc.gov/lccn/sn83030213/issues/