33 U.S. Code § 9. Des Moines River as toll free

The Des Moines River shall forever remain free from any toll, or other charge whatever, for any property of the United States, or persons in their service, passing along the same.

(R.S. § 5246.)
Codification

R.S. § 5246 derived from acts Aug. 8, 1846, ch. 103, § 3, 9 Stat. 78; Jan. 20, 1870, ch. 7, 16 Stat. 61.