The National Woman’s Party created their own flag to symbolize their struggles to achieve women’s suffrage. During the drive to ratify the 19th Amendment (the amendment which gave women the right to vote), they would sew on a star onto the flag for each state that ratified the amendment.
They used the flag when picketing the White House (unheard of at that time), parades and demonstrations. When the 19th Amendment was finally ratified, the leader of the party, Alice Paul, unfurled a flag with stars representing all of the States at their national headquarters in Washington, D.C.