876.13 Wearing mask, hood, or other device on public property.—No person or persons shall in this state, while wearing any mask, hood, or device whereby any portion of the face is so hidden, concealed, or covered as to conceal the identity of the wearer, enter upon, or be, or appear upon or within the public property of any municipality or county of the state.

also:

876.15 Wearing mask, hood, or other device at demonstration or meeting.—No person or persons over 16 years of age, shall, while wearing a mask, hood, or device whereby any portion of the face is so hidden, concealed, or covered as to conceal the identity of the wearer, hold any manner of meeting, make any demonstration upon the private property of another unless such person or persons shall have first obtained from the owner or occupier of the property his or her written permission to so do.