parts of Hawaii, southern California, southern Arizona, southern New Mexico, southern Louisiana, southern Mississippi, southern Alabama, southern Georgia, Florida, and most of Texas.
Ideally, the summer solstice is the day with the most sun. It's either June 20th or June 21st. It depends on the year, and what the government decides to publish it as. I've seen it vary a few times,...
States generally have pretty large areas, and many have a number of different climate zones. That makes it very difficult to say which "state" has the most sunny days a year. Las Vegas, Nevada and...