In case you hadn’t heard, Google is trying to do with newspapers what it’s been doing for some time now with books- make them all available on the Internet! You can search its News Archive right now:
A search for “St. Louis 1900s” gets 3,040 results (retrieves articles about St. Louis during the decade 1900-1910).
A search for “Kansas City 1900s” gets 2,050 results (retrieves articles about Kansas City during the decade 1900-1910).
Note: Some articles cited in your search results require payment before the article can be viewed online; you can always attempt to secure the article from another source once you have the citation!