The Rainbow River is located in Dunnellon, Florida, United States, in the southwest corner of Marion County, about 20 miles southwest of Ocala, 100 miles northwest of Orlando and 100 miles north of the Tampa Bay area. It is formed by a first-magnitude spring that is ranked fourth in the state for volume of discharge. In addition to the springs located at th…The Rainbow River is located in Dunnellon, Florida, United States, in the southwest corner of Marion County, about 20 miles southwest of Ocala, 100 miles northwest of Orlando and 100 miles north of the Tampa Bay area. It is formed by a first-magnitude spring that is ranked fourth in the state for volume of discharge. In addition to the springs located at the headwaters, there are many smaller springs that discharge from numerous caves, rock crevices, and sand boils the entire length of the river.