The Essex County Trail Association has scheduled 10-mile and 5-mile trail walks to celebrate the reopening of the Discover Hamilton Trail on May 18. The trail was originally created in the 1990s, and the association has been working with the town and landowners for the past year to make changes in the start of the route and elsewhere to make it safer and “more welcoming.” “People were using it,” said Ashley Hill, outreach coordinator for the association, who said that approximately 3 miles of the old path was on the side of main roads. “Now it’s almost entirely off the road,” she said. Starting from Patton Park on Bay Road at 9 a.m., the trail walk will include a 1.2-mile walk through the Myopia Schooling Field and Harvard Forest, and continue through the Massachusetts Department of Conservation and Recreation’s Bradley Palmer State Park, The Trustees of Reservations’ Appleton Farms Grass Rides, and Essex County Greenbelt Association’s Pingree Reservation. There will be a stop at the Topsfield Road footbridge at Bradley Palmer State Park for refreshments, and the walk will continue in a loop back to Patton Park, with walkers arriving at approximately 2 p.m. Leashed, well-behaved dogs are allowed on the trail, according to a release.