Google’s John Mueller answered a question about why some websites use multiple XML sitemaps instead of a single file. His answer suggests that what looks like unnecessary complexity may come from reasons that are not immediately obvious.

The question came from an SEO trying to understand why managing multiple sitemap files would be preferred over keeping everything in one place.

Question About Using Multiple Sitemaps

The SEO framed the issue as a matter of efficiency, questioning why anyone would choose to increase the number of files they have to manage.

They asked:

“Can I ask a silly question, what’s the advantage of multiple site maps? It seems like your going from 1 file to manage to X files to manage.

Why the extra work? Why not just have 1 file?”

It’s a good question, avoiding extra work is always a good idea in SEO, especially if someone has a relatively small website, it makes sense to have just one sitemap but as Google’s Mueller explains, there may be good reasons to split a sitemap into multiple files. See also: how do i split pages between brand building & converting?.

Mueller Explains Why Multiple Sitemaps Are Used

Mueller responded by listing several reasons why multiple sitemap files are used, including both practical and less intentional causes.

He responded:

“Some reasons I’ve seen:

• want to track different kinds of urls in groups (“product detail page sitemap” vs “product category sitemap” — which you can kinda do with the page indexing report)
• split by freshness (evergreen content in a separate sitemap file – theoretically a search engine might not need to check the “old” sitemap as often; I don’t know if this actually happens though)
• proactively split (so that you don’t get to 50k and have to urgently figure out how to change your setup)
• hreflang sitemaps (can take a ton of space, so the 50k URLs could make the files too large)
• my computer did it, I don’t know why”

Mueller’s answer shows that sitemaps can be used in creative ways that serve a purpose. Something I’ve heard from enterprise level SEOs is that they find that keeping a sitemap to well under 50k lines ensures better indexing. If you want to go further, decision coverage: why AI recommends some brands, not others covers it in detail.

Takeaways

Mueller’s answer shows that sometimes keeping things “simple” isn’t always the best strategy. It might make sense apply organization to the sitemaps appears to be unnecessary complexity is often the result of practical constraints, evolving site structures, or automated systems rather than deliberate optimization.

• Multiple sitemaps can be used to group different types of content
• They help avoid hitting technical limits like the 50,000 URL cap
• Some implementations are based on theory rather than confirmed behavior
• Not all sitemap structures are intentional or strategically planned

Featured Image by Shutterstock/Rachchanont Hemmawong