From Ohio History Central
While step ladders had existed for several years, on January 7, 1862, Dayton, Ohio, resident John H. Balsley received the first patent in the United States of America for such a device. Step ladders were named this because they resembled steps rather than traditional straight ladders. Previous to Balsley's patent, step ladders were not foldable for easy storage. Balsley placed hinges at the top of his ladder, allowing users to fold and store the ladder.