The United States Coast Guard Cutter Acacia (WLB 406) is one of 39 180-foot seagoing buoy tenders built for the United States Coast Guard between 1942 and 1944. Acacia was commissioned on September 1, 1944 in Duluth, MN and was one of the latter tenders built during the war effort. The cutter was named after the original United States Lighthouse Service Cutter Acacia (WLHS 200), that was sunk by a German U-boat off the British West Indies on March 17, 1944. The cutter is a multi-purpose vessel, nominally a buoy tender, but with equipment and capabilities for ice breaking, search and rescue, fire fighting, logistics, and other tasks.

Spending her career in Lake Michigan and Lake Huron, the cutter's last homeport was Charlevoix, MI where the ship's primary duty was maintaining more than 210 buoys, lighthouses and other navigational aids. Its area of operation ranges from as far south as Calumet Harbor, South Chicago, to as far north as Little Bay DeNoc, including Green Bay, WI; Sturgeon Bay, WI; and Wisconsin's Door Peninsula.

Among its various other duties were search and rescue of lost or disabled vessels and icebreaking assistance during the cold winter months. During the ice season, Acacia was one of several Coast Guard ice breakers engaged in Operation Coal Shovel, which keeps the channels between Toledo, Ohio and Detroit, MI open for the coal ships supplying power plants and industries in Detroit, MI.

In 1987-88, the cutter performed law enforcement patrols in the Caribbean before returning home to Lake Michigan. The cutter also worked with NOAA in their efforts to acquire accurate weather information and with the National Fish and Wildlife Service as they stock Lake Michigan with hundreds of thousands of yearling trout.

After 62 years of active duty, the Acacia was decommissioned on June 7, 2006, in Charlevoix, MI. Following a three week in-commission-special status the cutter and crew sailed to Burns Harbor, IN, where the cutter was formally transferred to AAI on June 30, 2006 to continue her service to the public as a historic, educational platform.

In the fall of 2009, the cutter was pilotated under her own power to her new home port of Manistee, MI and is now moored alongside the National Historic Landmark the S.S. City of Milwaukee.