The Castaways M.C. was incorporated November 1979 in Milwaukee, founded by Si Smits, Bob Pfeiffer, Tom Ryan, and a few other men. Formed largely as a split from the Silver Star Motorcycle Club, Castaways club members began by meeting each Sunday at the M&M Club, then went on a motorcycle ride. (Members recall that the two groups were strict rivals: Silver Star refused to allow dual memberships, so that if someone became a member of Castways, they would not be allowed to also be a member in Silver Star. Silver Star folded as an organization by the early 1980s.)

The Castaways has some trouble getting members as solely a motorcycle club, so in 1981 they went leather/ levi to open it up to more members. Over time it became more of a social group, at one point having up 21 members, although since the 1990's typically running 8-15 members.

Castaways held their first run in 1982. They changed to a joint run with the Argonauts of Green Bay in about 1996. They also typically held anniversary dinners at the Hotel Wisconsin. However Castaways has never owned a title.

According to their website in 2006: The Castaways M.C. (motorcycle club) is "a relaxed Leather/Levi social club located in Milwaukee, Wisconsin and are members of the Mid-America Conference of Clubs. We hold regular events in and out of the Milwaukee area. We also participate within our community and hold fund raising events through out the year. The third weekend of August, the Castaways M.C. join forces with The Argonauts of Wisconsin, another MACC member club, to hold our yearly run in Hilbert WI."

Their website in 2011 adds: "Since the beginning of our chapter, we've adopted a "service attitude" of giving back to the community that we live in and thrive in. You will see us at Pridefest and at our Club Events supporting our club and charities."

Castaways M.C. continues to co-sponsor (with Argonauts) an annual leather weekend Run in August. The Archives of the Castaways M.C. (plaques etc.) are stored with the Argonauts archives in the Annual Run building near Hilbert, WI.

Tom Ryan, 1999 (Co-Founder)	from Oberons: "Presented to Castaways in Brotherhood, November 1990"