diff --git a/Documentation/urls-remotes.adoc b/Documentation/urls-remotes.adoc
index 9b10151198..dba5adeb58 100644
--- a/Documentation/urls-remotes.adoc
+++ b/Documentation/urls-remotes.adoc
@@ -92,5 +92,44 @@ git push uses:
 ------------
 
 
+UPSTREAM BRANCHES[[UPSTREAM-BRANCHES]]
+--------------------------------------
 
+Branches in Git can optionally have an upstream remote branch.
+Git defaults to using the upstream branch for remote operations, for example:
 
+* It's the default for `git pull` or `git fetch` with no arguments.
+* It's the default for `git push` with no arguments, with some exceptions.
+  For example, you can use the `branch.<name>.pushRemote` option to push
+  to a different remote than you pull from, and by default with
+  `push.default=simple` the upstream branch you configure must have
+  the same name.
+* Various commands, including `git checkout` and `git status`, will
+  show you how many commits have been added to your current branch and
+  the upstream since you forked from it, for example "Your branch and
+  'origin/main' have diverged, and have 2 and 3 different commits each
+  respectively".
+
+The upstream is stored in `.git/config`, in the "remote" and "merge"
+fields. For example, if `main`'s upstream is `origin/main`:
+
+	[branch "main"]
+	   remote = origin
+	   merge = refs/heads/main
+
+You can set an upstream branch explicitly with
+`git push --set-upstream <remote> <branch>` or `git branch --track`,
+but Git will often automatically set the upstream for you, for example:
+
+* When you clone a repository, Git will automatically set the upstream
+  for the default branch.
+* If you have the `push.autoSetupRemote` configuration option set,
+  `git push` will automatically set the upstream the first time you push
+  a branch.
+* Checking out a remote-tracking branch with `git checkout <branch>`
+  will automatically create a local branch with that name and set
+  the upstream to the remote branch.
+
+[NOTE]
+Upstream branches are sometimes referred to as "tracking information",
+as in "set the branch's tracking information".