Site Collection
Common Use Cases
- Legacy SharePoint environments: older implementations built using sites and subsites
- Historical architecture references: documentation, blogs, and admin settings still referencing site collections
- Migration projects: moving from older subsite-based structures to modern flat architecture
- Governance discussions: understanding administrative boundaries in older SharePoint models
- Training and education: explaining the evolution of SharePoint architecture
Benefits
- Clear architectural evolution: encourages adoption of modern flat site design
- Simplified governance: each site stands on its own with clear ownership
- Improved flexibility: sites can be independently associated with hub sites
- Better scalability: avoids deep subsite hierarchies that were hard to manage
- Modern best practices: aligns with Microsoft’s recommended architecture
- Easier restructuring: sites can be reorganized without complex subsite dependencies
Details
- Feature Category: Sites & Navigation
How It Works
- Historical architecture: SharePoint historically grouped a top-level site and its subsites into one site collection that shared a storage quota, permissions, and site collection administrators
- Modern flat model: each new site is created as its own site collection with a single site inside it
- Hubs replace subsites: sites associate to a hub for shared navigation, branding, news rollup, and scoped search
- Site-level management: storage quotas, sharing settings, and site admins are still managed at the site (site collection) level
- Microsoft’s guidance: create one site per topic, project, or unit of work, then organize sites with hubs, not subsites
- The old vocabulary survives: PowerShell’s Get-SPOSite returns site collections, and older site settings pages still show site collection administration sections
Limits and Nuances
- Scale limits: a tenant can hold up to 2 million site collections, and a single site collection is capped at 25 TB of storage
- Storage quotas: they apply at the site collection level, and one busy library can consume the whole site’s quota, so monitor usage
- Subsites still exist: up to 2,000 are allowed per site collection, but Microsoft recommends a new site connected to a hub instead
- Permissions complexity: breaking permissions inheritance inside a site multiplies complexity; prefer separate sites over unique permissions when audiences differ
- Collection-wide scope: site collection features, audit settings, and the site collection recycle bin apply to everything inside the site collection
- Moving content is a migration: shifting content between site collections is not a drag and drop; plan for migration tools and link updates
- Plan the flat architecture: a flat model with no hub strategy leaves users guessing where things live, and hundreds of tiny single-purpose sites are as hard to govern as deep subsite trees
- One hub at a time: a site collection can associate with only one hub, and joining a hub does not change its permissions or storage
Common Questions About Site Collections
What is a site collection in SharePoint?
A site collection is a container that holds a top-level site and, historically, all of its subsites, sharing one storage quota and one set of administrators. In modern SharePoint, every site you create is its own site collection, so Microsoft now simply calls them sites. The term survives mostly in admin tools, PowerShell commands, and older documentation.
Is a site collection the same as a site in modern SharePoint?
Effectively, yes. Because modern SharePoint creates every new site as its own site collection containing a single site, the two terms now describe the same thing in practice. The distinction only matters in legacy environments that still use subsites, where one site collection can contain many sites stacked underneath a top-level site.
Should I still create subsites inside a site collection?
Microsoft recommends against it. Subsites lock you into a rigid hierarchy where permissions, navigation, and restructuring become painful over time. The modern approach is flat: create a separate site for each topic, project, or team, then connect related sites with a hub site for shared navigation, branding, and news rollup. Existing subsites keep working, but new builds should go flat.
How much storage does a site collection get?
Storage is pooled at the tenant level – your organization gets a base allocation plus an amount per licensed user, and sites draw from that pool. A single site collection can hold up to 25 TB. Admins can let SharePoint manage limits automatically or set manual quotas per site in the SharePoint admin center under Active sites.
How do hub sites relate to site collections?
A hub site connects independent site collections without merging them. Each associated site keeps its own permissions, storage quota, and administration, but gains shared navigation, a common theme, and news and search that roll up across the hub family. A site can belong to only one hub at a time, and you can re-associate it later as the organization changes.
Do I need to restructure my old site collections with subsites?
Not overnight, but a gradual move to flat architecture pays off in flexibility and easier governance. The usual path is to carve high-value subsites out into their own sites and connect them with hubs, retiring the old hierarchy in stages. This is exactly the architecture planning work Greg, the SharePoint Maven behind LookBook 365, helps organizations through during intranet projects.