At two separate locations near West Roxbury – one just less than a mile or two away and one just more than eight miles from Millennium Park – dogs are let off leash, allowing them to run free, socialize, and exercise.

So what makes that any different from Millennium Park, where dogs often run free despite the fact that it is against the law?

At the fenced-in dog parks at Peter's Park in the South End and Ronan Park in Dorchester, letting pooches off-leash is encouraged.

"It's a much more pleasant experience to walk your dog when not having to worry about upsetting someone," said J. Alain Ferry, the leader of BostonDOG, an organization that focuses on the establishment of dog parks in and across the city.

A recent incident at Millennium Park involving an off-leash and on-leash dog has prompted discussion about the need for a dog park at Millennium Park. Throughout the park, signs remind visitors that dogs must be kept on-leash, but they are frequently ignored.

Ferry explained the benefits to establishing a fenced-in dog park in a neighborhood, saying dog owners, the dogs themselves, and the community at large all see gains.

A dog park allows owners to further build camaraderie, Ferry said.

"It builds a community which already exists among dog owners," he said. "It encourages it and allows it to flourish."

Dogs benefit from the exercise they may not otherwise get, Ferry said.

And West Roxbury would benefit because it would keep off-leash dogs in an isolated area. A dog park can actually serve to see leash laws better enforced at a park, Ferry said, because when there is a clear spot where dogs can be kept off-leash authorities have no reason to allow them to run free throughout the park out of sympathy or understanding for the dogs' and owners' needs.

"A dog park becomes a powerful tool for enforcing leash laws," he said.

But not everyone supports the idea of forming a dog park in Millennium Park.

"I certainly wouldn't want to transition Millennium Park into a dog park," said Boston At-Large City Councilor and West Roxbury resident John Connolly.

Connolly said the city generally strives to help form dog parks in neighborhoods where there are more reported issues and incidents having to do with leash laws. He says he's never heard of an issue at Millennium Park.

"Ideally, we would hope for every neighborhood to have plenty of space for individuals and families and also for dogs and dog owners," he said. "Where there is not, we hope everyone respects the rules."

Millennium Park visitors are divided.

West Roxbury resident John Ioakimidis, who walks his shih-tzu Rocky on-leash, said it would "make sense" for a part of the park to be sanctioned for canines.

A Dedham woman who identified herself only as Rose disagreed. Rose lets her husky Kyah enjoy the entire park off-leash.

"She enjoys the freedom of the park," she said. "[A dog park] would ruin it. It's good to be able to walk around."

A Roslindale man who asked to remain anonymous does not own a dog, but said he has no problem with dogs being off-leash at the park. He said he would support the establishment of a dog park, provided it was big enough for the dogs to enjoy and get exercise.

However, the three visitors agreed about one thing. They all disagreed that there's a problem, and supported the status quo.

But Ferry said a status quo that sees dogs off-leash illegally as often as Millennium Park does is not acceptable.

"It's illegal," he said. "It's upsetting people. People are walking 100 feet out of the way to avoid your dog."

"Putting a dog park into an existing park generally resolves the problem," he added.

The process of establishing a dog park is a lengthy one. Though a Boston Parks and Recreation Department spokeswoman said the process could be as quick as three months, Ferry said two years is a much more likely period.

"It's a pretty lengthy, expensive process," he said.

Once a committee in favor of a dog park submits a proposal to the Parks and Recreation Department, it must then get the approval of neighborhood civic organizations and all abutters, Ferry said. It is then up to the committee to come up with the funding for its establishment, he said. Ferry estimated that a simple park could be set up for about $100,000, but that fundraising efforts for Ronan Park topped $285,000.

Ferry said the most vocal critics to dog park construction have generally been abutters. This might not be a problem at Millennium Park, which occupies a massive isolated area off the VFW Parkway and has its own parking lot.

Non- dog owners have also expressed resentment for the idea in the past, arguing that their tax dollars shouldn't have to pay for the maintenance of the park, Ferry said. But Ferry thinks that argument is narrow.

"A lot of dog owners only have their dogs as children," he said. "My tax dollars pay for playgrounds for children. I want a dog park."

On the contrary, dog owners often oppose the idea, preferring to simply let their dogs roam free at parks.

Just as there are opponents from both owners and non-owners, initiative for a dog park generally sees "bi-partisan" support, Ferry said.