Bring a large pot of lightly salted water to a boil. Add whole potatoes, and cook until tender, 15 to 20 minutes. Drain, run under cold water to cool, and chop into 1 inch cubes. Transfer to a large serving bowl, and refrigerate until completely chilled.

Meanwhile, stir ranch dressing mix, mayonnaise, and green onion together in a small bowl. Cover, and refrigerate for at least an hour to allow flavors to blend.

Wrap bacon in paper towels and place on a plate. Cook in the microwave until crisp, about 15 minutes depending on the power of your microwave. Set bacon aside to cool.

Add mayonnaise mixture to potatoes and toss to coat. Crumble bacon into the bowl, and stir briefly. Serve.