15. Davis, California
Home to the University of California at Davis, this thriving college town of 63,000 is as green as its residents are innovative. The university boasts top-rated resource economics, liberal arts, and agricultural programs. The campus has its own equestrian facility and dairy and meat processing plants, which employ many students. In Davis, bikes outnumber people and are the primary mode of transport around this quiet, yet vibrant college town.
