Edit: I'm not sure this will help, but I'll try: I am asking "what's the whole idea with wheels?"; a list of wheel parts is not what I am after. /edit

I'm aware that SPSite - despite the confusing use of a singular noun - represents a site collection, whereas SPWeb represents a (SharePoint) web site.

In order to begin getting a grip on SharePoint I thought it prudent to understand what these two things are. The MSDN documentation got me to the above understanding and not an inch further.

Googling "spsite vs spweb" leads to posts on here with nice diagrams showing how the site collection contains a root web site that is itself a website collection (since it may have subsites) and this bit is very clear.

What is not at all clear is why the makers of SP would bother to do it this way. Since SPWeb is in fact both a web site and a collection of web sites, what need is there for the site collection concept? What is it for?

I realize that it may be difficult to know if your understanding of these concepts is objectively accurate - it is inherently imprecise. Still, I would much appreciate if someone could give me some feel for these core concepts either by explaining in their own words, or by pointing me to someone else's words.

  • Well, thanks Eric! I specifically said that I have found the descriptions that say what it contains, and that this is not what I am after. I'm trying to understand what the thing is for. You are pointing someone asking "what's the idea with wheels?" to a post that says "a wheel consists of a hub, spokes, a rim, and a tyre", claiming this answers the question. I'm starting to suspect that nobody in the SP community understands what a site collection is any good for :p
    – The Dag
    Jun 30, 2015 at 14:44
  • since I can't post a real answer I will try to answer in comments. As Eric said, site collections are logical boundaries in the web application. As far as what that actually means, here are some examples: 1) site collections are the point where you can scale out into different content databases. A site collection can either be included in the main content DB for the web app, or be created with it's own content DB. SPWebs cannot have their own DB. 2) There is the concept of Site Collection Admins, who have admin privileges throughout all the SPWebs within the SPSite... [cont.] Jun 30, 2015 at 15:16
  • ... but may have little or no privileges on another site collection, and also they are not Farm admins, so they can't mess with services, etc. 3) As you probably have figured out, SP is organized around a concept of things inheriting down hierarchically. When you create a new site collection, the root SPWeb is provisioned with certain things that child SPWeb objects do not get, like the web part gallery, and the default display templates in the master page gallery. In addition certain other settings that apply to all SPWebs in a site collection are controlled from the root web of an SPSite. Jun 30, 2015 at 15:23
  • All the child webs inherit/use these things from the root web of the site. I know this wasn't much, but I hope it helps a little in your understanding of how SP works. Jun 30, 2015 at 15:24
  • @DylanCristy Thank you. What I wanted might be impossible, because there may not be any analogies or metaphores to draw on that would allow me to immediately "get it" and clearly see what each thing is/is for. But your answer gives me important clues about why there is a distinction. I'm a little surprised it is hard to find much writing on this subject, because these concepts are fairly core to SP and mastering them ought to be quite useful.
    – The Dag
    Jul 1, 2015 at 13:25

2 Answers 2


Site collections (SPSite) are logical boundaries in the web application. A SPSite is comprised of one or many SPWebs, the root web of a SPSite is a SPWeb.

  • SPWeb is a collection as well. Doesn't different webs provide enough of a logical boundary? I'm sorry, but your answer did not make the concepts any clearer for me at all. From my googling attempts so far, I'm not really convinced anyone knows what ideas, if any, may underpin this design.
    – The Dag
    Jun 30, 2015 at 14:27
  • a spweb is a collection of lists and libraries, a collection of lists and libraries is a different than a collection of webs Jun 30, 2015 at 14:57

Had this picture some time from another resource on the internet (can't remember which one, tho). This perfectly discribes the hierarchy:

enter image description here

You have a SharePoint farm (SPFarm) at the top and in that farm you have [0 to N] web applications (SPWebApplication), within one of those web applications you have a site collection (SPSite) and within that site collection you have [0 to N] sub sites (SPWeb) that can hold other sites (SPWeb). So basically, site collection (SPSite) is a placeholder for websites (SPWeb).

  • Sigh. This is the specific diagram I was making reference to! While it very clearly shows that SPSite is a container for SPWebs, it doesn't even hint at why it may be a good idea to have such a container. None of us would set out to put a lot of types into a library just to do so - we have some IDEA, some problem we are trying to solve, something..! Maybe the whole thing exists just so you can have more than one site at a top-level URL?!?
    – The Dag
    Jun 30, 2015 at 14:39

Not the answer you're looking for? Browse other questions tagged or ask your own question.