USS Achigan (YT/YTB-218) was a Cahto-class large harbor tug in the service of the United States Navy.

A French-Canadian rendering of the word ashigan which, in Chippewa and Algonquian dialects, is the name of the smallmouth bass.

Achigan (YT-218) was laid down on 23 July 1943, at Ipswich, Massachusetts, by W. A. Robinson, Inc.; reclassified a large harbor tug YTB-218 on 15 May 1944; launched on 4 October 1944; and placed in service on 9 January 1945.

On the afternoon of 8 January 1946, she sank at Philadelphia, as a result of a collision with General J. C. Breckinridge (AP-176).

The meager record of her service indicates that the tug served in the 6th Naval District into 1957, and was disposed of later that year.