Why can I clone the main repository but not a branch?

Question

I have a branch of a repository on github I am trying to clone. i can clone the main repository at the url https://github.com/pmyusername/myrepository (not actual link since the data is private). However, I cannot clone the branch located at https://github.com/myusername/myrepository/tree/branchname . To clone the repository, I simply needed to run:

git clone https://github.com/myusername/myrepository

but if i try to run:

https://github.com/myusername/myrepository/tree/branchname

I receive the error:

fatal: repository 'https://github.com/myusername/myrepository/tree/branchname' not found

but I know it exists because i am copying and pasting it from the url. The problem might have to do with the fact that I pay to keep it private, but i don't think so. Does anyone have any ideas?

Answer 1

I'll try to aggregate all the comments into a succinct response...
Step 1: git clone https://github.com/myusername/myrepository
Step 2: git fetch
Step 3: git checkout -b desired_branch # add origin/desired_branch to end of command line to set up remote tracking

UPDATE:
Just did a quick experiment with daniellarsson's suggestion, and it appears to work:
i:work> git clone -b metro git@github.com:user/project.git
i:work> cd project
I:\work\project> git branch -a
* metro
remotes/origin/HEAD -> origin/master
remotes/origin/master
remotes/origin/metro

Answer 2

If you use a UI like GitEx, you can mention the branch you want to clone in the dialog box the appears. This would clone the repo with the branch checked out automatically.