The swing arm holds the rod just above ground level.  The rod enters a pipe under a road showing how a rod line can be fashioned to avoid obstacles.

As the rod leaves the pipe, another pipe and hook assembly supports it.

Near its destination, the rod is suspended beneath another type of hanger called a "straddle bug" which brings it up to the height needed at the well site.  Often, the hangers for the rod were simply supported by conveniently located trees.  Rod lines were known to extend as much as 1/2 mile from the pumping power to the well site.   

At the well site, the rod is attached to the pump jack.  When pulled in tension by the pumping power, the horizontal motion of the rod operates the pump jack which produces the vertical motion required by the pump to perform the pumping stroke.  Many versions of the pump jack were built and all converted horizontal motion to vertical motion.  It seems that every foundry had its own version and many sold "kits" of the basic castings.  The producer supplied his own flat iron and pipe to complete the unit.  This pump jack is such an example.  This style became the most common and was later termed the "Oklahoma Jack" although it's design originated in Pennsylvania.