The Lake Hopatcong Block Party is a rain-or-shine event scheduled for Saturday, May 17, 2025, from 10 am to 4 pm, at Hopatcong State Park. It is an annual community event, hosted by the Lake Hopatcong Foundation, that brings people together with businesses, non-profit organizations, craft vendors, community groups, and food merchants for a fun-filled day that kicks off the summer season and celebrates all facets of Lake Hopatcong life. Thousands of guests enjoy lakeside shopping, food, entertainment, and demonstrations.