Florissant (/ˈflɒrɪsənt/ ⓘ) is a city in St. Louis County, Missouri, within Greater St. Louis. It is a middle-class, second-ring northern suburb of St. Louis. Based on the 2020 United States census, the city had a total population of 52,533. It is the largest city in St. Louis County.

The exact date the first settlers went to the Valley of Florissant is unknown, but it is one of the oldest settlements in Missouri. Some historians believe it was settled about the same time as St. Louis. The first civilian government was formed in 1786. Spanish archives in Havana reveal 40 people and seven plantations were in Florissant at the time of the 1787 census. The village, called "Fleurissant", meaning "Blooming" in English, by its French settlers and "St. Ferdinand" by its Spanish rulers, was a typical French village with its commons and common fields. Originally a separate town, and now an inner suburb of St. Louis, the community was centered on (and frequently called after) the parish of St. Ferdinand. The center of the parish, the Old St. Ferdinand Shrine, survives and is listed on the National Register of Historic Places.[citation needed]

Around 1809, the Cold Water Cemetery had the first burial; since 2004, it has been listed in the National Register of Historic Places for its social history.

As late as 1889, the town was predominantly French-speaking (while the southern portion of the metropolis was populated by German speakers). The first train line to the area was constructed in 1878—an extension of the line which went from St. Louis City to Normandy. The last train to Florissant ran on November 14, 1931.

Following World War II, Florissant went from a small village community to a large suburban center, as developers such as Alfred H. Mayer Co. began building subdivisions on what was formerly farmland and empty acreage. Around 18,000 houses were built between 1947 and 1980, and the population swelled to its peak of about 76,000 in the mid-1970s, making it the largest city in St. Louis County.

James J. Eagan was the first mayor of Florissant after a charter amendment created the position. He ultimately served 37 years from 1963 until his death on November 2, 2000, being re-elected into office nine times, and became one of the longest-serving mayors of any city in the United States. In his final year, he was awarded the title of Best Politician in St. Louis by the Riverfront Times. The civic center off Parker Road is named the James J. Eagan Community Center in his memory.

In 2012, Florissant was ranked 76 in Money magazine's top-100 list of Best Places to Live – America's Best Small Cities. In 2014, Florissant ranked as the #1 Best Small City to Retire To in America and the second-safest city in Missouri.

Florissant Old Town Historic District is a locally designated historic preservation planning district, created by local ordinance in 1969. Within that, the heart of Old Town Florissant is listed on the National Register of Historic Places as the St. Ferdinand Central Historic District. The boundaries of the district are roughly rue St. Francois, rue St. Ferdinand, and rue St. Denis, and Lafayette Street. The City of St. Ferdinand Multiple Resource Area (MRA), located in the oldest section of the present city of Florissant, encompasses approximately 156 city blocks and encloses the approximate area of the City of St. Ferdinand, as Florissant was known from 1857 to 1939. This MRA comprises 124 historically significant properties ranging in date from 1790 to 1940. The historic Old St. Ferdinand Shrine is located on the western end of Old Town. The Shrine and Historic Site consists of four historic buildings on their original locations: the 1819 convent, 1821 church, 1840 rectory, and 1888 schoolhouse. It is listed individually on the National Register of Historic Places and is a U.S. Historic District.

Historic Florissant, the local historical society, operates out of the preserved Gittemeier House.

According to the United States Census Bureau, the city has a total area of 12.87 square miles (33.33 km2), of which 12.56 square miles (32.53 km2) are land and 0.31 square mile (0.80 km2) is covered by water.

The 2020 United States census counted 52,533 people, 19,702 households, and 12,336 families in Florissant. The population density was 4,185.9 per square mile (1,615.9/km2). There were 21,769 housing units at an average density of 1,734.6 per square mile (669.6/km2). The racial makeup was 46.34% (24,345) white, 44.79% (23,529) black or African-American, 0.24% (125) Native American, 1.01% (530) Asian, 0.03% (14) Pacific Islander, 1.5% (790) from other races, and 6.09% (3,200) from two or more races. Hispanic or Latino of any race was 2.7% (1,393) of the population.

Of the 19,702 households, 26.1% had children under the age of 18; 39.3% were married couples living together; 34.1% had a female householder with no husband present. Of all households, 30.7% consisted of individuals and 12.2% had someone living alone who was 65 years of age or older. The average household size was 2.6 and the average family size was 3.2.

23.1% of the population was under the age of 18, 8.4% from 18 to 24, 27.2% from 25 to 44, 25.2% from 45 to 64, and 13.6% who were 65 years of age or older. The median age was 36.9 years. For every 100 females, the population had 90.9 males. For every 100 females ages 18 and older, there were 93.1 males.

The 2016-2020 5-year American Community Survey estimates show that the median household income was $58,769 (with a margin of error of +/- $4,467) and the median family income was $73,794 (+/- $3,536). Males had a median income of $36,440 (+/- $2,203) versus $33,166 (+/- $2,612) for females. The median income for those above 16 years old was $34,998 (+/- $1,688). Approximately, 7.9% of families and 10.2% of the population were below the poverty line, including 17.2% of those under the age of 18 and 5.2% of those ages 65 or over.

At the 2010 census, there were 52,158 people, 21,247 households and 13,800 families living in the city. The population density was 4,152.7 inhabitants per square mile (1,603.4/km2). There were 22,632 housing units at an average density of 1,801.9 per square mile (695.7/km2). The racial makeup of the city was 58.3% White, 36.8% African American, 0.2% Native American, 0.8% Asian, 0.6% from other races, and 2.3% from two or more races. Hispanic or Latino people of any race were 2.0% of the population.

There were 21,247 households, of which 32.3% had children under the age of 18 living with them, 42.4% were married couples living together, 17.5% had a female householder with no husband present, 5.1% had a male householder with no wife present, and 35.0% were non-families. 29.9% of all households were made up of individuals, and 12.2% had someone living alone who was 65 years of age or older. The average household size was 2.42 and the average family size was 3.00.

The median age in the city was 38 years. 23.9% of residents were under the age of 18; 8.6% were between the ages of 18 and 24; 26.2% were from 25 to 44; 25.8% were from 45 to 64; and 15.5% were 65 years of age or older. The gender makeup of the city was 46.8% male and 53.2% female.

At the 2000 census, there were 50,497 people, 20,399 households and 13,687 families living in the city. The population density was 4,442.4 inhabitants per square mile (1,715.2/km2). There were 21,027 housing units at an average density of 1,849.8 per square mile (714.2/km2). The racial makeup of the city was 86.66% White, 10.51% African American, 0.20% Native American, 0.61% Asian, 0.03% Pacific Islander, 0.52% from other races, and 1.48% from two or more races. Hispanic or Latino people of any race were 1.49% of the population.

There were 20,399 households, of which 30.7% had children under the age of 18 living with them, 49.8% were married couples living together, 13.2% had a female householder with no husband present, and 32.9% were non-families. 28.8% of all households were made up of individuals, and 12.3% had someone living alone who was 65 years of age or older. The average household size was 2.44 and the average family size was 3.01.

24.7% of the population were under the age of 18, 8.2% from 18 to 24, 29.9% from 25 to 44, 20.0% from 45 to 64, and 17.1% who were 65 years of age or older. The median age was 37 years. For every 100 females, there were 89.5 males. For every 100 females age 18 and over, there were 84.1 males.

The median household income was $44,462 and the median family income was $52,195. Males had a median income of $37,434 compared with $27,247 for females. The per capita income for the city was $20,622. About 2.7% of families and 4.0% of the population were below the poverty line, including 4.5% of those under age 18 and 3.7% of those age 65 or over.

Florissant is covered by the Hazelwood and Ferguson-Florissant public school districts. McCluer North High School and McCluer High School of the Ferguson-Florissant School District, and North Technical High School are high schools in Florissant. Hazelwood Central is the only high school in Florissant belonging to the Hazelwood School District. Hazelwood Northwest Middle School and several elementary schools are also within the municipal limits.

North County Christian School is a pre-school to grade 12 Christian school that is theologically associated with the Church of the Nazarene.

There are several kindergarten through 8th-grade parochial schools in Florissant. These include Atonement Lutheran School, Sacred Heart, St. Ferdinand, St. Rose Philippine Duchesne and Saint Norbert.

Florissant has a theological college, an extension campus, and a barber college. Saint Louis Christian College is a private, four-year, undergraduate institution that is theologically and ecclesiastically associated with the Christian Churches and Churches of Christ. Lindenwood University has its offsite North County Campus located in the former Our Lady of Fatima School. Missouri School of Barbering and Hairstyling-St Louis is also located in Florissant.

St. Louis Community College–Florissant Valley and University of Missouri–St. Louis are located in close proximity to the city.

St. Louis County Library operates the Florissant Valley Branch in Florissant.

Florissant is home of a number of examples of Missouri German architecture, mostly in brick commercial and institutional buildings,

The finest example in the area is the Kuehn House, which has a "pronounced, toothed corbel table on its primary facade"; other notable examples are the Tebeau House and the Withington House. Each of these is individually listed on the National Register of Historic Places. Several more examples are in the National Register-listed St. Ferdinand Central Historic District:

It is also home to numerous Missouri French architecture examples, mostly wood frame residences. Examples include: