You don't need an <a> element to use the "id" attribute (in XHTML "name" is not allowed), but you can add it to any other element. Like this:
<p>This is a <a href="#bottom">link to the bottom</a> of the page.</p>
<p id="bottom">And this is the bottom of the page.</p>
If both "id" and "href" end up in the same file after splitting (if necessary), you don't need the full URL; otherwise, as cuthbert19 says, you'd need to write the relative path from one file to the other.