Lake Istokpoga is a 26,762.9-acre freshwater lake in Highlands County, Florida. It is fed by two creeks, Arbuckle Creek and Josephine Creek. The oblong-shaped lake is approximately 5 miles wide by 10 miles long. It is considered the fifth largest lake in the state of Florida. Despite its area, it is very shallow, with an average depth of only 4 feet. Maximum depth iā¦Lake Istokpoga is a 26,762.9-acre freshwater lake in Highlands County, Florida. It is fed by two creeks, Arbuckle Creek and Josephine Creek. The oblong-shaped lake is approximately 5 miles wide by 10 miles long. It is considered the fifth largest lake in the state of Florida. Despite its area, it is very shallow, with an average depth of only 4 feet. Maximum depth is 10 feet. As a result, boaters must be cautious to not become stranded in muck near the shore line. Bass and pontoon boats are the most commonly used watercraft, with some use of airboats. With such shallowness, this lake is extremely dangerous for boaters during windstorms, as the waves get quite high.