Millis High School has been named one of the nation's best in a ranking by Newsweek magazine. The magazine compiled the country's top 1,000 schools based on a series of criteria, and Millis ranked 629th, with 96 percent of students graduating and 94 percent matriculating to college. Twenty-one Massachusetts schools made the list, including Hopkinton High, ranked at 161; Dover-Sherborn High, at 147, and Ashland High, 596.