Thursday, April 19th through Sunday, April 22nd 10am-4pm. As part of the ongoing campaign to make Ulster the healthiest county in New York, Mohonk Preserve is offering a free, one-month membership for residents of Ulster County. Visitors with proof of Ulster County residency may obtain their passes at the Preserve Visitor Center from 10am to 4pm Thursday, April 19th through Sunday, April 22nd and at the Spring Farm Trailhead from 10am to 4pm Saturday, April 21st and Sunday, April 22nd. The membership passes will be valid through May 20, 2018. Passes must be picked up in person, with the exception of minors, whose parent or guardian may pick up a pass on their behalf.