Acadia National Park
Acadia is one of the smaller national parks in the country, yet it attracts nearly 3 million visitors per year. It is important that those who do visit and explore this wonderful park follow some basic guidelines in order to keep the park as clean, natural, and undisturbed as possible. Please review the Leave No Trace principles  if you're planning a trip, and remember them while you are having a great vacation. Help keep Acadia the way it should be. Friends of Acadia  is a group that offers additional details about respecting this natural wonder.
Originally designated as Sieur de Monts National Monument in 1916 by presidential proclamation, Congress renamed the park Lafayette National Park in 1919. Congress again enacted a name change in 1929 to the name we now use, Acadia National Park. It was the first NP established east of the Mississippi River.
In October 1947 Acadia, along with some adjacent lands, was ravaged by fire.
A quick look at any topographical map of Mount Desert Island will indicate the powerful and lasting effects of the last ice age on the island and the current landscape of Acadia. As the last glacier receded over 18,000 years ago it left behind the elongated mountains and lakes we see today. The moving ice was also the culprit behind the "bald" summits of most of the park's hilltops, scraping off vegetation and leaving the beautiful pink granite underneath.
Flora and fauna
More than 273 bird species have been identified in the park, including bald eagles, peregrine falcons, blue jays, finches, and chickadees (the Maine state bird). Mammal species include deer, squirrels, foxes, rabbits, porcupines and bats. Other species include garter snakes, the American bullfrog, and the North American red-bellied salamander.
The National Park's checklist of common plants can be found here 
Acadia is accessible through a number of routes, the most clearly-defined are the Hulls Cove Visitor's Center  and the park entrance on Schooner Head Road.
The free Island Explorer Buses, Phone: +1 207 667-5796,  can take you through the park, stopping at points of interest. There are bicycle racks on the front of each bus if you'd like to combine transport methods as you explore.
Acadia is a great place to birdwatch, with many species calling the park home. Bald eagles, peregrine falcons, great blue herons, cranes, ducks, geese, chickadees, woodpeckers, owls, orioles and blue jays can be seen in the park, just to name a few of the most common. For an extensive checklist and more info on birdwatching opportunities in Acadia, see the NPS's birdwatching page here 
Acadia has the best day hiking in the Eastern U.S. Walking the miles of trails is one of the best ways to experience the park. Immerse yourself in the flora and fauna of the island on a number of different hikes of various environment, length, and difficulty. These trails are stunning, with high ocean views, accessible tree lines, steep precipices, stone bridges, etc.
The last glacier of 18,000 years ago carved out the incredible and beautiful terrain of the park, leaving behind some of the cleanest lakes and ponds in the country.
Toll free: +1 888-533-WALE, .
Apart from the campgrounds, those looking to see the 'real' Maine can look into more adventurous places to sleep. The Park is full of locations where one can set up a pup tent for the night, although it is advised to do so at discretion, pack light, and leave no trace.