Hi, @JoeMark, and welcome to our Netlify community site.
The _redirects file should be in the publish directory for your site. The “publish directory” is where your sites files are stored after the site is built.
For some static site generators, that directory is indeed named “public”. If this is the correct directory for you or not will depend on what directory your static site generator (SSG) uses for storing the files created during the build process.
Let me take Hugo as an example.
Hugo deletes the contents of “public” before building and then stores all built files there. However, any files included in the directory “static” are copied to “public” during the build. So, for Hugo you should put the files in “public”.
There are two ways to do this. You can either manually copy the file there as the last step of the build or keep the file in “static” and Hugo will copy it to “public” for you automatically. (If you are using Hugo, I recommend doing it this second way).
If you tell us which SSG you are using, we can give an answer specific to that SSG. Please let us know if there are other questions about this and we’ll be happy to answer.