KevinR, Interesting. It looks like Cadillac grabs the earliest sunrise from Katahdin, but not for the whole year. Just like the seasons affect the case for the last sunset, they seem to affect the case for the first sunrise.
The Naval Observatory had this to say about the first sunrise on just Jan 1 (not the rest of the year), "If the territories are not included the earliest sunrise is ... at the summit of Cadillac Mountain, Maine (44° 21' N 68° 13' W). ... For those who thought it would be the peak of Katahdin Mountain, Maine, the Sun rises there 1 minute later at 12:07 UT or 7:07 EST."
http://aa.usno.navy.mil/faq/docs/first_sunrise.html#USKatahdin (45° 54' N) is further north than Cadillac (44° 21' N). Because of this and because Katahdin's sunrise was only a minute later than Cadillac's on Jan 1, in the good ol' summertime it looks like Katahdin has an earlier sunrise than Cadillac. (I didn't check real carefully but it sure looks that way.)
"At 1,532 feet, Cadillac Mountain in Acadia National Park is the highest point along the North Atlantic seaboard (see photos) and is the first place to view sunrise in the United States from October 7 through March 6."
http://www.acadiamagic.com/CadillacMountain.htmlAgain, I didn't check real carefully but it appears that Cadillac Mountain and Mt. Katahdin take turns having the earliest sunrise. Cadillac from October 7 to March 6, and Katahdin from March 7 to October 6. However, Porcupine Mountain has been mentioned as a close contender with Cadillac on Jan 1. Porcupine has a latitude of 44° 57' which is slightly north of Cadillac, so Porcupine might have the earliest sunrise for awhile after March 6 and for awhile before October 7. Not sure.