Abstract: A tension rod anchor includes a collar that defines a ball race and a ball jack that includes a ball head that forms a swivel joint with the ball race. The ball jack also includes a threaded shaft that engages with a threaded socket of a hosel, which also includes a rod channel that receives a railing rod. A set screw engages with a threaded hole through a side of the hosel into the rod channel. The set screw engages with an anchor hole in the rod, without bearing against the threaded shaft, while the hosel is screwed onto the threaded shaft to tension the rod. Once the desired tension has been obtained, the set screw is screwed down further and tightened to secure the rod with the rod under tension. The swivel joints allow rod railings to be easily installed at angles and inclines.