Family and followers of Daniel Boone settled the area starting in 1799. In 1814 a ferry boat was licensed for crossing the Missouri River to the north and the settlement became known as Washington Landing. In 1827 a town was laid out, with sale of lots starting in 1829. The cost of land was waived if the buyer could build a substantial house within two years. This encouraged many new settlers.
Substantial numbers of anti-slavery German families started moving to the town in 1833, and they soon overwhelmed the existing population of slaveowners. Washington became a strong supporter of the Union during the American Civil War. The town was ransacked by Confederate General Sterling Price's troops, but they were unable to keep control of the area and he retreated with them to Mexico.
After the war, Washington became a railroad and steamboat transportation center. Its manufacturing industry has remained strong since that time. Washington is the location of Missouri Meerschaum, Inc., the largest factory in the world for corncob smoking pipes.
The town of Washington has 445 buildings on the National Register of Historic Places, a state record. Due to its historic charm, Washington has a growing heritage tourism industry, with visitors also attracted to the nearby Missouri Rhineland.
There were 5,258 households out of which 32.7% had children under the age of 18 living with them, 53.7% were married couples living together, 9.1% had a female householder with no husband present, and 33.4% were non-families. 28.4% 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 2.46 and the average family size was 3.04.
In the city the population was spread out with 25.7% under the age of 18, 8.7% from 18 to 24, 30.3% from 25 to 44, 19.4% from 45 to 64, and 16.0% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 91.5 males. For every 100 females age 18 and over, there were 88.7 males.
The median income for a household in the city was $43,417, and the median income for a family was $52,433. Males had a median income of $36,163 versus $23,666 for females. The per capita income for the city was $22,360. About 3.0% of families and 5.0% of the population were below the poverty line, including 4.1% of those under age 18 and 4.7% of those age 65 or over.