If you were an unmarried man in the Chicago suburb of Aurora, Ill., in 1948, you would likely have spent Leap Day in jail. As documented in a LIFE photo essay by George Skadding, on that day the city’s women took their posts as mayor, fire chief, police chief and police officers and imprisoned men for the crime of being single. As the magazine explained:
The single women of Aurora weren’t the only ones who saw Leap Day as a rare opportunity. The day has long been associated with a kind of Sadie Hawkins-esque special permission for women, instead of men, to initiate marriage proposals. The murky origins of the tradition point to unverifiable Irish and Scottish folklore, while variations on the theme include the Finnish custom that a man who refuses a woman’s Leap Day proposal must pay her a fine, in the form of enough fabric from which to fashion a skirt.
Many today view Leap Day for Single Ladies as a sexist custom, in that it designates one day out of every four years for female empowerment but doesn’t challenge the patriarchal traditions that continue uninterrupted on all other days. But in Aurora seven decades ago, when a female police chief was so unimaginable to as be nothing more than a Leap Day farce, the day offered a taste of what the future might bring.
Liz Ronk, who edited this gallery, is the Photo Editor for LIFE.com. Follow her on Twitter @lizabethronk.