When Nicole Ramos hikes in Acadia National Park, she is elated she can bring Lucy, her Jack Russell Terrier.

Otherwise, she is unsure of what she would do. “I’d probably be disappointed and maybe have to go somewhere else,” said Ramos, 35, of Camden, Me., while starting a hike with Lucy along the Asticou & Jordan Pond Path in Acadia.

Of the 59 national parks, Acadia is in the minority in keeping dogs and owners together on hiking trails. In fact, Acadia is among only a few national parks – Shenandoah in Virginia is another – that allow dogs and other pets on trails, as long as they are leashed, according to the National Park Service.

When they plan a trip to Acadia, dog owners are generally happy to discover that they don’t need to leave their pets at home or place them in a kennel if they want to hike.

“I couldn’t put them in a kennel,” said Todd Long, a water well service contractor from Brevard, N.C., who was walking on the Cadillac Summit Loop Trail with Chelsea and Daisy, his two Jack Russell Terriers, during his first-ever visit to Acadia.

“They are too spoiled. They are used to being with me,” said Long.

(See Acadia on My Mind’s new page for Top 5 hikes for dogs)

Dogs often climb peaks in Acadia.

Carolina Garces and James Falzarano, both 24, of Boston, said they hiked with their mixed-breed, Olaf, to the top of 1,248-foot Pemetic Mountain, the fourth highest in Acadia.

“It was steep,” said Garces, a nutritionist, during a break from a hike along the Asticou & Jordan Pond Path. “We were wondering if he could do it.”

Dogs can even hop aboard the Island Explorer, a fare-free shuttle bus that operates in Acadia late June through Columbus Day.

Alison Reynolds, a registered nurse, and her husband, Peter Reynolds, a retired public school principal, from Vermont, exited the bus at Jordan Pond with their Standard Poodle, Dodger.

Dodger hiked with them on trails such as Wonderland and Ship Harbor Trail, two of the best in the park for dogs.

“You bet,” Peter Reynolds said when asked if Dodger would be at their side on a planned hike to Beech Mountain.

Other best hikes for dogs include Bar Island Trail, Compass Harbor Trail, Schooner Head Path, Great Meadow Loop, Beech Cliff Loop, and Ocean Path.

Pets are also welcome at Blackwoods and Seawall campgrounds, but not at the Duck Harbor campground on Isle au Haut.

Where you can’t let the dogs out

Great Smoky National Park, Yellowstone, Yosemite, Glacier, Rocky Mountain and several others generally ban dogs from hiking trails, according to the park service.

Dogs are permitted on 12 miles of paved trails above the rim on the South Rim of the Grand Canyon, but they are banned from the inner canyon, shuttle buses and almost all North Rim trails.

At Yellowstone, the nation’s first national park, a faithful pet can’t get near Old Faithful. Dogs are also prohibited in the back country and on trails and boardwalks such as the one for Old Faithful Geyser.

What fun is it if you can’t bring your dog on a hike?

“It’s safe to say we wouldn’t have come to the park today if dogs were not allowed,” said Ken Nicholls, of Silver Springs, Md., who was walking on Cadillac with his Welsh Corgis, Howie and Robbie. “It’s certainly a factor. We like traveling with them.”

“I don’t have children,” added Nicholls, a retired chief operating officer with the ALS Association. “We enjoy them. They like the exercise. We like the exercise. It’s a fair deal.”

“Embrace dogs? ” one reader commented on a 2013 National Parks Traveler article about dogs and national parks. “In most every park, dogs are confined to parking lots or front range campsites.”

In banning dogs from trails, parks cite factors such as possible clashes with native wildlife, pet escapes, possible bear attacks and maybe exchanges of diseases among animals.

To the north of Acadia, dogs and other pets are banned altogether from Baxter State Park, home to the spectacular 5,268-foot Mt. Katahdin.

In Acadia and other parks, dogs must be on a leash no longer than 6 feet and owners must remove pet waste.

Dog owners often violate the leash rule, especially in the back country.

According to Charlie Jacobi, natural resource specialist for Acadia, surveys have shown that the percent of owners who abide by leash rules can be as low as 38 percent and as high as 55 percent.

Acadia’s rules for pets

Even in Acadia, dogs are banned from certain ladder trails such as the Precipice, Beehive, Perpendicular and Jordan Cliffs.

In addition, “there are many other trails or sections of trails for which it is difficult to keep your dog on a leash because they are so rugged,” said Jacobi, including the Giant Slide, Pemetic Northwest, Spring, Parkman Mountain, Acadia Mountain, Bubbles (heading from South Bubble to Jordan Pond), Sargent East Cliffs and Cadillac West Face trails.

“I would not recommend any of these to hikers with dogs, and there are some others that are almost as tough,” said Jacobi in an e-mail. “My advice — ask a ranger.”

Pets are allowed on all 45 miles of carriage roads, but there are other rules that affect access.

For example, pets are prohibited from beaches during the swim season and Wild Gardens of Acadia at Sieur de Monts.

Rangers have been known to rescue injured or lost dogs in Acadia.

About 15 years ago late in March, for example, a ranger drove celebrity Martha Stewart and her dog off a carriage road, because the dog couldn’t walk.

The dog needed the ride because it had just had foot surgery.

Stewart owns an estate in Seal Harbor on Mount Desert Island.

If you’re hiking a restricted trail or swimming at Sand Beach or Echo Lake when they’re off-limits to pets, you can always leave your dog with a local pet sitter.

It’s not just Acadia National Park that is pet friendly. It’s also the surrounding community and businesses.

For instance, there’s Bark Harbor in Bar Harbor, a pet supply store that often features pictures of visiting dogs on its Facebook page. On its Web site, Bark Harbor even lists pet-friendly lodging and restaurants.

And the Eastern National store in the Hulls Cove Visitor Center offers “Bark Ranger” items like leashes, which are also available online at eParks, the online store for national parks (see eParks ad in sidebar).

In fact, dogs are more welcome than some people. While dogs are allowed on about 100 miles of Acadia’s hiking trails, people on bikes are prohibited from all hiking trails. Bicyclists, hikers and horses are allowed on carriage roads.