The advocacy group Parks & Trails New York said the rally is in response to a state parks plan that closes 41 of 178 parks, reduces services at 23 others and shuts down 14 of 35 historic sites because of New York's budget crisis.
Five other Long Island parks may close swimming pools and reduce picnic areas. The cuts and closures are subject to the State Legislature's approval.
Gov. David A. Paterson's budget proposal for fiscal 2010-2011 cuts $20 million from the parks agency.
On Long Island, about 150 protesters gathered Saturday at Orient Beach and 700 at Heckscher State Park.
Earlier this week, parks officials said they had canceled hundreds of campsite reservations at 12 state parks that could be closed this year.
Advocates say closing parks will reduce state revenues and hurt local economies.
With Gary Dymski