Almost 250 years ago, surveyors Charles Mason and Jeremiah Dixon placed a marker at the spot where Maryland, Delaware and Pennsylvania now intersect. That modest marker was on private land, though, making its exact location something of regional mystery.

But on June 6, which is National Trails Day, the public can walk to the site, as well as enjoy the complete northern segment of the trail to the marker.  At 11 a.m., hikers will carry flags from Pennsylvania, Delaware and Maryland to the spot for a brief ceremony.

The celebration will be held rain or shine, and includes a self-guided 1.7 mile hike along the new Tri-State marker Trail, with various organizations presenting activities and information along the way.  The hike ends at the Tri-State Marker. 

Discovery stations include "Surveying the 18th Century Way," "The Mason-Dixon Survey History in the Tri-State Region," a display of native plants, a wildlife identification station, information about the Eagle Scout projects that contributed to the trail, as well as information about Lyme disease, and information about the Wilmington Trail Club.  Maps will be provided at the trailhead, and the trail will be marked with signs and chalk markings.  Visitors should start the hike before 10 a.m. to allow time to see the discovery stations along the route before the dedication ceremony.

Access to the trailhead is from the parking lot on Arc Corner Road (off Chambers Rock Road), in Pennsylvania.  West Grove Fire Company Fire Police will be directing traffic at this intersection from 9 a.m. to 1 p.m. 

The effort to complete the trail began in December 2011, when the State of Pennsylvania purchased the Pennsylvania lands around the marker. The parcel connected to other holdings in the White Clay Creek Preserve. Although the land was under state ownership, access was difficult. Only unmarked trails, some through marshes and stream crossings, were available.

Friends of White Clay Creek Preserve partnered with the Wilmington Trail Club to work with Pennsylvania to construct a trail to the Tri-State Marker.  Throughout 2012 and 2013, a trail plan was developed, and presented to the Pennsylvania Department of Conservation and Natural Resources. 

The Tri-State Marker Trail is about four miles long,  connecting the White Clay Preserve’s Arc Corner parking lot with the marker.  There are connecting trails to the Carpenter Area of White Clay Creek State Park in Delaware. The pedestrian trail has 15 bridges and boardwalks.

The long history of proposals for the area began in the early 1960s, when there were plans to build a dam on the White Clay Creek at Wedgewood Road, in Newark, Del., to provide water for Delaware residents. The project would have flooded the White Clay Creek from Newark into Landenberg. The DuPont Company purchased all but about 300 acres of the valley, up to the 175-foot elevation, in anticipation of needing this new water source in New Castle County. 

In Delaware, opposition to the project began with a coalition between the Delaware Sierra Club, the United Auto Workers Union, and concerned citizens. In Pennsylvania, residents along the White Clay Creek who refused to sell their land formed a group to oppose the project. Their concerns were that Pennsylvania land was being taken to supply Delaware with water. They were also concerned that large mud flats would be created in Pennsylvania when the reservoir was drawn down.

Eventually the Pennsylvania opposition came together with the active group from Delaware, and in 1965, the White Clay Watershed Association was incorporated. The group worked to help New Castle County solve its distribution problems by sharing water among the state’s various water companies.

In 1984, the DuPont Company donated 1,350 acres of land to the states of Delaware and Pennsylvania, creating the White Clay Creek State Park and Preserve. It ended the plan for the dam.

For more information, and a list of all the hikes that will be leading to the marker on June 6, visit www.FriendsofPaWCCP.org.