The Thousand Islands region surrounding Theresa, New York sits at an elevation of approximately 400 feet above sea level, characterized by its proximity to Lake Ontario and the St. Lawrence River. Summer temperatures typically range from 65-85°F between June and August, with evening temperatures dropping into the 50s. Campgrounds in this area provide access to water recreation along approximately 1,800 miles of shoreline throughout the Thousand Islands.
What to do
Water activities on the St. Lawrence: Waterfront sites at Jacques Cartier State Park provide direct river access for kayaking and swimming. "Everyone swims, kayaks, and paddle boards off their sites," notes a visitor to Jacques Cartier State Park Campground. The park includes a guarded beach area with a playground nearby for younger children.
Island exploration: The Thousand Islands region features numerous islands accessible by boat or bridge. "You're 10 min from Alexandria Bay. Boldt castle, singer castle, you can go on river cruises and view these beautiful islands and homes on them. Watch the cargo ships cruise the channel," shares a camper at Wellesley Island State Park.
Nature trails and wildlife viewing: Wellesley Island State Park Campground offers miles of hiking trails along the water. "I really recommend heading to the nature center and following the trails there. The views are gorgeous and you get some great vistas," advises a visitor who appreciates the natural setting.
What campers like
Waterfront views and sunsets: The region's location provides exceptional sunset viewing. At Sun Outdoors Association Island, campers rave about the scenery: "Sunsets were phenomenal! I mean, jaw dropping gorgeous," shares one visitor. Sites facing west provide direct views of Lake Ontario sunsets.
Spacious sites: Many campgrounds offer generously sized sites, particularly those away from peak tourist areas. At Natural Bridge/Watertown KOA, "The sites are small, but there are mature trees between them & woodsy areas around the campsites," notes a recent visitor who appreciated the layout and privacy.
Fishing opportunities: The St. Lawrence River and Lake Ontario provide excellent fishing. "Great fishing on the St. Lawrence is awesome!!! Catch some perch and have a fish fry back at camp! If you fish near the boat rental there is a place to clean your fish!" shares an enthusiastic angler who stayed at Wellesley Island State Park.
What you should know
Seasonal operation: Most rv parks near Theresa, New York operate from May through mid-October. Brennan Beach Campground runs from "May 1 to October 15," according to their listing, which aligns with most campgrounds in the region. Winter camping options are extremely limited.
Wind conditions: Lake Ontario's shoreline experiences significant winds. At Sun Outdoors Association Island, a camper warned: "It is very windy here and found very few windows to paddle. Our neighbor (who has camped here seasonally for the last four years) mentioned that he lost three awnings to the wind."
Reservation requirements: State parks like Jacques Cartier require advance booking for summer weekends. "We book early so we can get a water front site," advises a regular visitor, indicating the popularity of premium locations during peak season.
Tips for camping with families
Swimming areas with supervision: Several parks offer designated swimming areas with lifeguards. At Jacques Cartier State Park, "There's a great guarded beach if you have young ones with a newer playground right next to it," shares a parent, providing peace of mind for families with children.
Kid-friendly amenities: Swan Bay Resort - The 1000 Islands Premier RV Park & Marina features recreational options for children. "The playground is awesome and huge with lots of cool features for kids to explore," notes a visitor, highlighting facilities specifically designed for younger campers.
Educational opportunities: "We camped here with one of our children, and had a wonderful time canoeing, fishing, and spending time together!" shares a parent who visited Wellesley Island State Park, where the nature center provides learning opportunities about local ecology.
Tips from RVers
Concrete pads at premium sites: RV sites with concrete pads provide stability regardless of weather conditions. At Ontario Shores RV Park, "There are 7 overnight pull thru full hookup sites with concrete patio. Sites are level and spacious," reports a motorhome owner, noting the quality of the parking surfaces.
Wind protection strategies: When camping near Lake Ontario, secure awnings and external equipment. According to a Sun Outdoors Association Island visitor, "Don't leave your awning out when you leave your camper and beware of winds if you want to be on the water."
Supply accessibility: For RV campers staying at Swan Bay Resort, "Within walking distance is a Price Chopper Grocery, Dollar General, gas station, and wine and liquor store," making it convenient to restock supplies without disconnecting.
