XML Sitemaps help search engines find, crawl, and index the pages on your website. There’s no penalty for not having one, but creating an XML Sitemap is relatively simple and can be very beneficial for getting more of your website’s pages ranked, so we highly recommend them. For small, relatively simple websites—those with only a few hundred pages—a single XML Sitemap is fine. However, sometimes a single XML Sitemap is not sufficient for large or complex websites.
The Limitations of Single XML Sitemaps
A single XML Sitemap can be used to list all the pages on your website—up to 50,000 URLs or 10MB. So, the first limitation of a single XML Sitemap is size. It’s not uncommon for enterprise websites and/or large e-commerce websites to have far more than 50,000 unique pages. For these sites, a single XML Sitemap will not be adequate. Instead, you’ll need to create an XML Sitemap Index and include inside the file the addresses of additional Sitemaps. How you break up and organize your site depends on your business.
Let’s say you’re the webmaster of a large non-profit association. Your website has about 70,000 unique pages. The range from standard pages like the homepage, about page, leadership, etc. to thousands of industry-specific research articles organized by date, topic, author, etc. Your site also has events and products for sale (an e-commerce component). In this scenario, you might want to break your XML Sitemaps into an Index, a Sitemap for your main pages (home, about, etc.), a Sitemap for your research articles, and a Sitemap for your events (especially if you have a lot of them or you keep archived information after they are finished), and finally, a Sitemap for your products (e-commerce portion of the site).
The Benefits of Using Multiple XML Sitemaps
Besides allowing sites with more than 50,000 URLs to communicate the existence of all their pages to the search engine, there’s another benefit to using multiple XML Sitemaps. When you create an XML Sitemap and upload it to Google Webmaster Tools and verify it, you can see how many pages of your site have been submitted vs. indexed. Great, right? The trouble is, with single XML Sitemap, you can’t see which pages are indexed and which are not.
If your site is small and you have a decent set of SEO tools, it’s not too hard to figure out which pages are the problem. When you have a large website, diagnosing indexing issues can be far more difficult. Are your un-indexed pages a few random products within your website store or some old and poorly linked blog posts? Using multiple XML Sitemaps—categorized by the various sections of your website—you’ll be able to see whether your indexing issues are your product pages or your blog posts.