High Quality Content by WIKIPEDIA articles! The Rainbow River is located in Dunnellon, Florida, USA, in the southwest corner of Marion County, about 20 miles (32 km) southwest of Ocala, 100 miles (160 km) northwest of Orlando and 100 miles (160 km) north of the Tampa Bay area. It is formed by a first-magnitude spring (Rainbow Springs) 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.