The Imperial River is a river in southwest Florida in the United States. It is fed by the Kehl Canal and marshland at (26°22′16″N81°41′23″W), just east of the city limits of Bonita Springs in unincorporated southwest Lee County. It is approximately 9.3 miles (15.0 km) long, from its headwaters just east of I-75 in the Flint Pen Strand, through downtown Bonita Springs and to its mouth at the north end of Fishtrap Bay, near the southern end of Estero Bay. It was originally named Surveyors Creek before the city was developed.