Mantua was settled in the mid-19th century when members of The Church of Jesus Christ of Latter-day Saints were sent by Lorenzo Snow to the valley to grow flax. The first group arrived in Mantua in 1863, and were all emigres from Denmark and their local leader was Hans Jens Jensen. Snow was from Mantua, Ohio, and the town was named after the Ohio community in his honor. Prior to receiving its current name, the community had various name, including: Box Elder Valley, Copenhagen, Flaxville, Geneva, Hunsaker Valley, Little Copenhagen, and Little Valley.
As of the census of 2000, there were 791 people, 218 households, and 189 families residing in the town. The population density was 162.5 people per square mile. There were 231 housing units at an average density of 47.5 per square mile. The racial makeup of the town was 96.33% White, 0.63% African American, 0.51% Native American, 0.25% Asian, 0.51% from other races, and 1.77% from two or more races. Hispanic or Latino of any race were 0.88% of the population. There were 218 households out of which 52.8% had children under the age of 18 living with them, 79.4% were married couples living together, 5.0% had a female householder with no husband present, and 13.3% were non-families. 12.4% of all households were made up of individuals and 5.5% had someone living alone who was 65 years of age or older. The average household size was 3.63 and the average family size was 4.01. In the town, the population was spread out with 38.2% under the age of 18, 10.1% from 18 to 24, 23.3% from 25 to 44, 20.1% from 45 to 64, and 8.3% who were 65 years of age or older. The median age was 30 years. For every 100 females, there were 108.7 males. For every 100 females age 18 and over, there were 103.8 males. The median income for a household in the town was $60,234, and the median income for a family was $61,964. Males had a median income of $42,100 versus $26,875 for females. The per capita income for the town was $17,798. About 0.5% of families and 1.7% of the population were below the poverty line, including 2.1% of those under age 18 and 3.4% of those age 65 or over.
Government
Mantua is still considered by some to be a speed trap. In 1997, its two police officers issued over 1,300 speeding tickets, amounting to fines of approximately $60,000, or more than half of the city's total yearly revenue. In 2014, it issued over 2,100 traffic tickets, amounting to approximately $220,000 in fines, or more than one-third of total yearly revenue. The sole full-time police officer objected to the term "speed trap" as he said he did not hide his truck, and fatal accidents have decreased since he began patrolling. Most tickets are issued along the town's section of U.S. Routes 89/91. However, a state legislator counters that reduced speed limits, installed barriers, and rumble strips have reduced traffic fatalities, calling into question the justification for such a large ratio of issued traffic tickets in the area. In January 2020 Mantua once again came under fire for unethical revenue sources, as they were issuing parking tickets on land not owned by the city, and with signage knowingly being installed wrong. They had also increased their budget for parking fines 24% over the previous year. When questioned about this the city claims they lose money on parking tickets which is in contrast to the rest of the state. Brigham City owns the land which the tickets were written on, and the Mantua PD was operating with unapproved Brigham City employees telling them when to issue citations.
