Blue Spring is a first-magnitude spring located along the St. Johns River. A first-magnitude spring is a spring that discharges at least 100 cubic feet of water per second and about 64.6 million gallons per day. It was visited by the famous early botanist John Bartram in 1766 and in 1856 was bought by a previous gold rush prospector turned orange-farmer, Louis Thursby. Since the land he bought was along the river it soon became a plethora for steamboat activity. A variety of tourist and shipped goods passed through their land and Mrs. Thursday even became a post mistress, the first in Orange City. The railroads were built in the 1880's and Blue Spring became less of a social hot-spot, but it became a crucial place for one of the most vulnerable populations.
In 1971 a film was produced at Blue Springs called "The Forgotten Mermaids." It was a unique documentary that recorded the importance of Blue Springs for the endangered Manatees in the winter. The Manatees would migrate to Blue Spring as a warm spot in the colder months of Florida and would return every year. The manatees however in the process would receive injuries from boat strikes, fishing line entanglements, and cold lesions. This led to a lot of scars and even fungal infections. These scars actually helped researchers identify different Manatees year after year. This enlightening film led to Florida State to buy the property and turn it into the state park it is today. In 1972 Manatees were officially put under protection by the Federal Marine Mammal Protection Act and as recently as 2016 was taken off the endangered list and downgraded to only the threatened list. Today visitors can enjoy Blue Spring State Park along with the Manatees. Popular activities include Bird Watching, Eco Boat Tours, Camping, Fishing, Hiking, paddling, picnicking, scuba diving, snorkeling, swimming, and tubing. The park includes amenities like cabins, campgrounds, canoe kayak launch, concession stands, dump stations for RV, and of course the historic Thursby House. Blue Spring State Park is a must visit not only for a glimpse of the majestic manatees as, but the beautiful large spring that started it all.