Hi,
I cam across a circuit in my house that is wired like this:

It comes out of the breaker box, to an outlet, from that outlet up to the 2nd floor to another outlet, then into the adjoining room to an outlet in there, up the wall to a junction box. From the junction box it goes to a two other outlets in the same room and to the switch for the light.

My question is, is it OK to have it wired like that? Or does a main run have to go right to a junction box?

Thanks,

There really isn't much to say about this other than... the parts you describe are within code. I can't tell you if everything about the circuit is up to code, but using a junction box in this manner is fine as long as it is accessible. The code does not require a junction box on this circuit at all but the fact that they used one is also fine.