The Carolina Thread Trail began with the germ of an idea: Identify the region’s most pressing environmental need.

It grew into a vision, launched in 2007, of hundreds of miles of trails that would connect parks, neighborhoods, towns, conservation areas and regional attractions across 15 counties.

On Saturday, the Thread marks its fifth anniversary and 100th mile of trail, to be commemorated by a monument at Davidson’s West Branch Nature Preserve Trail.

“We started out thinking this would be a 500-mile network,” said project director Ann Browning. Instead, communities and counties embraced the idea, drawing plans for 1,400 miles of trails.

A National Association of Realtors survey cites walking and biking trails as the top amenity homebuyers prefer. Trails offer easy access to exercise, get kids outdoors and keep pollutants out of streams.

But local leaders say the Thread also helped pull together a far-flung region of 2 million people. Inspired by its possibilities, communities found common ground as they worked together to plan trails.

The Gaston County town of Belmont won a $30,000 Thread grant in 2010 to assess putting a greenway along a Piedmont & Northern rail line. When work on the 1.5-mile trail begins next year, with $1.4 million in state grants, it will connect downtown Belmont to Belmont Abbey College and pave the way for future links.

“What the Thread Trail offered us was an opportunity to connect our town with other towns and also some things outside the town center,” said Mayor Richard Boyce. “Our dream is for someone to be able to get on a bike and ride from the Belmont Abbey campus on our north to Stowe Botanical Garden on the south side.

“The larger dream is that soon you’ll be able to walk or jog from Belmont to Mount Holly, and someday to Mountain Island Lake.”

The Thread staff helps communities plan trails, find money to build them, and offers technical expertise. Thread projects have won more than $21 million in public money, protecting 1,300 acres the trail will cross. The Thread itself has added $3 million in privately funded grants.

The Catawba Lands Conservancy, a local land conservation group, is the lead agency for the Thread Trail, working with five other land trusts in the region. The Foundation For The Carolinas, which began the process that gave rise to the Thread, is its leading foundation supporter.

“The Thread Trail staff is amazing,” said Charlie Lieske, president of the Baxter Trail Club in Fort Mill, S.C. “They’re all willing to listen and talk and direct you to resources. They really share the passion and therefore are very willing to take the time.”

Lieske is among the Thread’s trained Trail Masters, who leads a corps of nearly 500 volunteers in building and maintaining trails. More than half the 6 miles of wooded trail in Baxter, a planned community, are part of the Thread.

To be included in the regional network, trails have to connect one county to another. Master plans developed by local committees aim to include a diversity of neighborhoods and points of interest, and often identify other trails that won’t be part of the Thread.

Thread grants and state money helped Concord leverage its $15,000 into $635,000 in grants for a greenway it’s building along 13 miles of the Rocky River.

Mayor Scott Padgett said trail rights-of-way will only grow harder to come by as years pass and the region builds out.

“As we look back in years to come we will appreciate the efforts that were made,” he said. “The Thread Trail plan has been an impetus for us to move forward on greenways, and there will never be another time like right now.”