United States, Minnesota, Itasca, Coll. Site #67. NE1/4SE1/4 Sec.21 T55N R25W; Grand Rapids. Marsh directly under the bridge where Hwy.169 crosses the Mis Coll. Site #67. NE1/4SE1/4 Sec.21 T55N R25W; Grand Rapids. Marsh directly under the bridge where Hwy.169 crosses the Mississippi River in Grand Rapids.. 055N 25W 21