Alpena Harbor is located at mouth of the Thunder Bay River which empties into Thunder Bay, Lake Huron. The harbor is 100-miles southeast of Cheboygan Harbor, Mich. The Thunder Bay River has its source in Montmorency and Alpena Counties, Mich. The project was authorized by the Rivers and Harbors Acts of Sept. 19, 1890; March 2, 1919; Sept. 22, 1922; Aug. 30, 1935; and Oct. 27, 1965. The existing project provides for a bay channel 200-feet wide and 25-feet deep from deep water in Thunder Bay to a point 300-feet lakeward of the Alpena Light; thence an entrance channel 24-feet deep, narrowing to a width 100-feet at a point 700-feet upstream from the light; a river channel 100-feet wide, 23-feet deep to the Second Avenue Bridge; thence 18.5-feet deep and 75-feet wide for 1,600-feet to the upper limit of the Federal project; a turning basin at the upstream end of project; and a breakwater about 700-feet long paralleling the south side of the entrance channel at the shoreline. Several commercial docks, which are used primarily for receipt of coal and petroleum products, exist along the river. A cement production facility exists adjacent to the outer harbor area. A municipal marina basin is located about ¼ miles southwest of the river channel mouth.