Acadia National Park squeezes granite peaks, forest, and rocky Atlantic shoreline into just 65 square miles on the Maine coast — one of the smallest yet most visited national parks in the US. Its headline attraction is Cadillac Mountain, which at 1,530 feet is the highest point not just in the park but along the entire Eastern Seaboard. And the easiest way to the top is one of the prettiest short drives in American national parks: the Cadillac Summit Road.
The seasonal road runs 3.5 miles up to a bare granite summit with 360-degree views over Bar Harbor, Frenchman Bay, and the Porcupine Islands. Pullouts along the narrow two-lane climb let you stop for coastal panoramas, and short paved trails criss-cross the top. Most visitors spend about two hours on the drive, and it scores 4.8 on Tripadvisor from more than 3,800 reviews — the kind of rating that's hard to argue with.
The big draw is timing. From early October to early March, Cadillac is geographically the first place in the United States to see the sunrise, and sunrise and sunset slots are the most popular — arrive very early for parking, and expect company. Weather shifts fast up there, with fog and wind common, so bring layers.
A few practicalities make or break the trip. The road opens around April 15 and closes December 1, conditions permitting. Between May 20 and October 25 you need a timed vehicle permit ($6 at the time of writing, sold only in advance on Recreation.gov) on top of the park entry pass. Vehicles over 21 feet — RVs and trailers — can't handle the tight curves, and there's no public transit to the summit. Alternative: the free Island Explorer shuttle drops hikers at the Cadillac North Ridge Trail for a 4.4-mile round-trip walk to the top. In winter, when the road shuts, hiking is the only way up, though 45 miles of car-free carriage roads stay open for biking, snowshoeing, and skiing.
The summit drive pairs naturally with the park's 27-mile Loop Road, which threads past steep coastal cliffs and offshore islands on the eastern side of Mount Desert Island. The Summit Road turnoff sits about two miles south of the Cadillac Mountain Entrance, roughly ten minutes from Bar Harbor, which makes the town an ideal base.
Acadia is also worth knowing as a park built by generosity — the first in the US created through donated private land, by philanthropists in the early 1900s, with its roads deliberately designed to show off the island without wrecking it.
Summer is busiest, with daytime temperatures ranging from 45 to 90°F and quick weather changes; spring and fall are cooler and often foggy, while winter highs sit between 14 and 35°F with road and facility closures. For elbow room, go in the shoulder seasons or midweek in summer — or skip the famous viewpoints and hunt out the park's quieter corners.