How Google still finds an orphan page, or misses it
Googlebot finds new URLs to crawl mainly through links in pages it has already crawled. An orphan page cuts that path. On large sites it is harder to make sure every page is linked from at least one other page, so Googlebot may miss new pages. Pages reachable only through a site's search box may not be found, because Googlebot generally does not submit searches while crawling.
A sitemap is the usual way out. Google can also discover pages from a submitted sitemap, which is how an unlinked page may still be found. Listing a URL in a sitemap helps discovery, but Google may still not crawl or index it.
A found orphan still starts weak. Google can use how many links point to a page and how many clicks it takes to reach it to judge its importance within a site. An orphan has no internal links and no click path, so both signals are missing.
Detecting orphans by comparing URL lists
In Search Console, the Links report lists the pages on your site that link to a given URL. Google says the Links report shows only a sample of internal and external links, and some URLs may be left out, such as non-indexed or deduplicated pages. So the report can support a suspicion but cannot prove a page is orphaned. Finding orphans takes a comparison of two lists:
Collect every URL you know exists: the XML sitemap, analytics landing pages and server logs.
Crawl the site from the homepage, following links only.
Subtract the crawled list from the first list. The URLs left over are your orphans.
Common causes
Two causes come up often. The first is navigation without real links. Googlebot generally follows only links written as an a element with an href. The second is a migration. Google's site-move guide says to update internal links to the new URLs. Pages that the new navigation or templates no longer link to become orphans.
How to fix an orphan
Link it. Google suggests linking to a page in context from other pages that help readers understand it.
Redirect a duplicate. Google recommends redirects to get rid of duplicate pages, and a permanent redirect only when deprecating a duplicate.
Remove it. For a page that should not exist, a 4xx response such as 404 or 410 makes Google remove the URL from its index; Google treats all 4xx codes except 429 the same.
For the content side of a migration, see the step-by-step CMS migration guide.
For crawlable navigation on a Next.js site, see Next.js SEO optimization.
Sources
- Page indexing report - Search Console HelpGoogle · support.google.com
- Link best practices for GoogleGoogle · developers.google.com
- What Is GooglebotGoogle · developers.google.com
- What Is a SitemapGoogle · developers.google.com
- Help Google understand your ecommerce website structureGoogle · developers.google.com
- In-Depth Guide to How Google Search WorksGoogle · developers.google.com
- Links report - Search Console HelpGoogle · support.google.com
- Site Moves and MigrationsGoogle · developers.google.com
- How to specify a canonical URL with rel="canonical" and other methodsGoogle · developers.google.com
- How HTTP status codes, and network and DNS errors affect Google SearchGoogle · developers.google.com