Which finger do women wear the engagement ring on?

In the United States the tradition is for a woman to wear her engagement ring on the ring finger of her left hand. As shown in the picture, the ring finger is the one next to the pinky.

Note: Some people define the ring finger as the "fourth digit", "third finger", "second most ulnar finger" and the list goes on, but I find it easiest to call it the finger between the middle finger and the little finger.

More about which finger does one wear an engagement ring on:
Historically the ring finger was believed to have a special, direct connection to the heart by way of the vena amoris, the vein of love. My research leads me to believe this is more a myth than medical fact, but the ring finger has veins and veins are connected to the heart so romantics can still embrace the romantic story of the ring finger being connected in a special way to the heart.

More about which hand is the engagement ring worn:
I couldn't find too much explanation for why the left hand has become the tradition. I imagine it has to do with the heart being located on the left side of the body which ties in with the whole vein of love concept as well. Also, people tend to be right handed so maybe wearing rings on the left has something to do with that. Regardless, in the U.S. the tradition is to wear the engagement ring as well as wedding rings on the left hand.

All Pre-Engagement Questions: