If your navigation contains many links and comes before the main content in the DOM, add a Skip to main content link before the navigation (for a simple explanation, see this A11Y Project article on skip navigation links). Using the .sr-only class will visually hide the skip link, and the .sr-only-focusable class will ensure that the link becomes visible once focused (for sighted keyboard users).
More Information in the WCAG 2.0 Guidelines
G1: Adding a link at the top of each page that goes directly to the main content area
<body>
<a href="#content" class="sr-only sr-only-focusable">Skip to main content</a>
...
<div class="container" id="content" tabindex="-1">
<!-- The main page content -->
</div>
</body>Chrome/Internet Explorer Issues
Due to long-standing shortcomings/bugs in Chrome (see issue 262171 in the Chromium bug tracker) and Internet Explorer (see this article on in-page links and focus order), you will need to make sure that the target of your skip link is at least programmatically focusable by adding tabindex="-1".
In addition, you may want to explicitly suppress a visible focus indication on the target (particularly as Chrome currently also sets focus on elements with tabindex="-1" when they are clicked with the mouse) with #content:focus { outline: none; }.
Note that this bug will also affect any other in-page links your site may be using, rendering them useless for keyboard users. You may consider adding a similar stop-gap fix to all other named anchors / fragment identifiers that act as link targets.