Thursday, April 20th through Sunday, April 23rd 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 20th through Sunday, April 23rd and at the Spring Farm Trailhead from 10am to 4pm Saturday, April 22nd and Sunday, April 23rd. The membership passes will be valid through May 21, 2016. Passes must be picked up in person, with the exception of minors, whose parent or guardian may pick up a pass on their behalf.