The Hopkinton Trails Club will host a group walk at the Duck Pond Trail on Sunday, April 21, at 1 p.m. This often-overlooked system of trails is located behind the Hopkinton State Park headquarters (where participants should park) on the west side of Cedar Street. The main trail goes over to Duck Pond, off Saddle Hill Road, and other trails form loops that can be followed. The walk covers moderate terrain and will take about two hours. For more information, visit hopkintontrailsclub.com.