Libraries usually offer access to newspaper archives which you can search. Often this requires a login of some type if used online, or physical presence at the library.

These archives usually aren't publicly available since it takes a lot of effort to digitize newspapers from the past, and it is difficult and expensive to keep the archive up to date. The entity running the archive will want some compensation for that. So libraries subscribe to the archive for a fee, and they in turn give their members access to it. For instance many university libraries offer access to LexisNexis News.

You could try NewpaperCat which is kind of the half sister of Worldcat. Its not huge, but barring access to the subscriptions of an archive or library might be a good choice. If you are thinking more hardcopy the Repository of Primary Sources is a massive list of archives.