Maine’s Internet superhighway has been completed six months ahead of schedule and within its $31.7 million budget, looping through the state to connect more than 100 communities from Skowhegan to Perry to Frenchville.

The 10 gigabit network, which is fast enough to download a feature film in half a second, will provide the backbone for high-speed Internet access to benefit rural communities and attract businesses to the state, according to telecommunications experts.

The Three Ring Binder project is named for the three rings of fiber-optic networks that circle through rural western, eastern and northern Maine. It spans 110,000 households, 600 schools, libraries and other institutions and 38 government buildings. For the first time, the state has a direct high-speed link to Halifax and Boston.

Before the Three Ring Binder project, international data traveled under sea to Halifax, surfaced there, then went back underwater — bypassing Maine entirely — to Boston. That meant a computer file sent from a Maine business to an overseas destination would travel first to Boston, then underwater to Halifax before going overseas.

The high-speed Internet network also allows doctors at Mid Coast Hospital in Brunswick to consult in real time with stroke specialists at Maine Medical Center in Portland. In addition, students at the University of Maine’s Machias campus can watch lectures from professors across the country.

Other uses include providing mental health counseling through video conferencing to patients who are house-bound, or giving businesses the ability to locate in Maine that previously needed to be closer to high-tech centers with faster bandwidth.

“It’s already being used in ways I hadn’t considered and by more companies than we ever imagined,” said GWI Chief Executive Fletcher Kittredge. “It’s being used by businesses and commercial users that in the old days couldn’t be in Maine. Now they can be.”

The project prompted the U.S. Chamber of Commerce last year to designate Maine as having the best business infrastructure in the country, but the state still trails in residential high-speed Internet access.

About 61 percent of Maine households have broadband access, slightly below the U.S. average of 63 percent, and behind New England peers such as New Hampshire at 73 percent and Massachusetts at 70 percent, according to the Federal Communications Commission.

“It puts us on the map internationally. National and international carriers now have access to Maine that they never had before,” said Jeff McCarthy, vice president of business development for Maine Fiber Co.

“We’re the backbone going into really remote areas.”

The core network was finished June 30, ahead of the December 31 goal, said Dewey Allison, vice president of Maine Fiber.

Maine Fiber was formed as a private company that’s unaffiliated with any telecom carrier to oversee the Three Ring Binder construction, and to maintain and lease the network.

GWI is a customer on the Three Ring Binder network and one of the key players in bringing the high-speed network to Maine. About a dozen customers are already on the network, and another two to three dozen in negotiations to connect to the network, said Dwight Allison of Portsmouth, N.H., Dewey Allison’s father and one of the lead investors in the project.

The network has roughly 185,000 strand miles and only 10.8 percent, or roughly 20,000 strand miles, are committed to customers so far. The entirely above-ground network is strung along 29,000 telephone poles.

The project is the so-called middle mile, or the heavy trunk line, that connects anchor institutions such as the University of Maine campuses, as well as the Internet service providers that sell bandwidth to individual customers.

No single entity can use more than 20 percent of any segment of the network.

The network is the highway, essentially. The Internet service providers and telecommunications companies still have to provide the last mile links, or the on-ramps to the highway, directly to homes and businesses.

It will increasingly be available to more residents as Internet service providers build out the last mile links.

The project, which included a $25.4 million in federal stimulus grant, as well as $7.4 million in private investment, had enough funding to allow some extra connections. Examples include the final 5,000 feet linking Calais to Canada, and two connections into New Hampshire, said Dewey Allison.

Maine businessman Robert Monks is one of the lead investors in the project. Monks is a board member of MaineToday Media, which owns The Portland Press Herald/Maine Sunday Telegram, the Kennebec Journal in Augusta, the Morning Sentinel in Waterville and other media outlets in Maine.

Monks and Dwight Allison helped attract about 75 private investors to raise the $7.4 million in private funding to launch the project. The investments range from $25,000 to more than $100,000, Dwight Allison said. He would not say how much he invested in the project.

The project is expected to break even around the beginning of 2013, but it is several years away from paying dividends to investors, Dwight Allison said. Investors should see a reasonable return over the course of the project, Monks said.

The project started more than three years ago as a group of Maine state officials, representatives of the University of Maine System, GWI and others got together in early 2009 to determine how the state might tap into some funds set aside through the American Recovery and Reinvestment Act to improve access to broadband Internet service.

“The big driver behind it all was to get the level of service and capacity to our more rural campuses,” said Jeff Letourneau, executive director of NetworkMaine, a unit of the University of Maine System. “As we got east, west and north, the options for connectivity weren’t the same, and those students were at a disadvantage.”