Federal Census for 1880
By 1880 the population of New Philadelphia had plummeted to 84 individuals, a reduction of 31% from the 122 individuals reported in 1870 and a 48% decline from the town's population peak of 160 residents in 1865. The number of 17 households in 1880 represents a reduction of 41% from the town's peak of 29 households in 1865.
While New Philadelphia's population declined, the state of Illinois' population continued to grow. In 1880, the state's population included 3,077,871 people, an increase of 21.2% over 1870's number of 2,539,891.
Black individuals living in Illinois now numbered 46,368 representing 1.5% of the state's total population, and reflected an increase of 61.2% over the 28,762 included on the 1870 federal census. In New Philadelphia, white residents, 70 individuals, or 83% of the population, continued to maintain the majority racial representation of the town. New Philadelphia's 14 black and mulatto individuals represented the minority, 17% of the populace.
Most of New Philadelphia's townsfolk, 20 individuals, or 24% of the total population continued to be occupied in farming. That number represents 64%, or 31 individuals gainfully employed outside the home. A school teacher, a store keeper, a house servant and a blacksmith also lived in the town. Thirty-two individuals, 38% of the populace, were recorded as "at home." For children "too young to be involved in production," census enumerators were instructed to mark the occupation column of the census form "at home." The town's 28 children 14 years of age and under are reflected in the "at home" group. However, other individuals listed as "at home" ranged from infants to 34 years of age, another indication that census enumerators sometimes took liberty with interpretation of their instructions.
The majority of the town's residents, 67 individuals, or 80% of the population, originated from the Great Lakes region of the United States. Fifty-two individuals, or 62% of the population, were Illinois natives, including 29 adults and 23 children under 14 years of age.