What is a Root Domain?

Root Domain is the highest hierarchical level of a site and is separated from the Top Level Domain by a dot (e.g. rootdomain.com).

The term root domain means different things depending on if you’re talking about the Internet as a whole or about your website.

Technically, the root domain is the highest hierarchical level of the Internet, even above top-level domains such as .com and .net.

root domain in DNS
Outside of the context of DNS, your root domain commonly means the highest level of hierarchy for the website you control. In the example below, the root domain starts at the microsoft.com node and includes everything branching from it in blue.

your root domain
Image: Microsoft

The root domain microsoft.com encompasses subdomains such as mydomain.microsoft.com and www.microsoft.com as well as webpages branching from the main site and any subdomains. The following are all examples of locations within the root domain, microsoft.com:

  • microsoft.com
  • microsoft.com/about
  • www.microsoft.com/about
  • mydomain.microsoft.com
  • mydomain.microsoft.com/about
  • blog.microsoft.com/news/newthing.html

When you register a website name or domain name, you are registering a root domain. This means you have the access to create subdomains and file structures all branching from that root domain.

If Google equates a specific subdomain with quality, this can influence how webpages within that subdomain rank in search results. For this reason, how your website is structured can affect how well your content ranks in search results.

In marketing it’s also useful to track how many high quality links are pointing to your website. This is a ranking factor affecting how high your content could ranks in search results.

The number of links pointing to your website at the root domain level is the numbers of links pointing to any pages within your main website or within any subdomains. Tools like Majestic can estimate how many links are pointing within your root domain, a specific subdomain, or to a single web address.

Root Domain Resources

Root Domain Experts


  • Domain Name
  • Root Directory
  • Second-Level Domain