The town grew up around Ottawa Indian settlements. The tribe lived in the area from 1837 to 1867 and donated land for Ottawa University. The town and university were named for the tribe.
The city of Ottawa has a history of flooding due to the Marais Des Cygnes river. One of the first big floods which was noted happened in 1844, twenty years before the city's founding in 1864. No official measurements were taken, though was estimated to be at 40 feet (12 m). A flood in 1928 had a crest point of 38.65 in which 6 people died. Other flood years include 1904, with a crest of 35.8 feet (10.9 m); 1909, cresting at 36.3 feet (11.1 m); 1915, cresting at 31 feet (9.4 m), and 1944 cresting at 36.5 feet (11.1 m).
However, it is the Great Flood of 1951 which is the most famous. It was about five inches higher than the 1928 flood. The flood of 1951 affected much of Missouri and Kansas and 41 people died. 1/3 of Ottawa was covered because of this flood.
It is unlikely that Ottawa will suffer major damage due to a flood again thanks to a series of levees and pumping stations built by the U.S. Army Corps of Engineers in the 1960s. It is actually part of a larger system of flood systems to regulate the Marais Des Cygnes river all the way to the Missouri River. The levees built along the river are inspected on an annual basis to insure their quality.
According to the United States Census Bureau, the city has a total area of 6.7 square miles (17.4 km²), of which 6.7 square miles (17.3 km²) is land and 0.15% is water.
Climate
Over the course of a year, temperatures range from an average low of about 20 °F (−7 °C) in January to an average high over 90 °F (32 °C) in July. The maximum temperature reaches 90 °F (32 °C) an average of 52 days per year and reaches 100 °F (38 °C) an average of 6 days per year. The minimum temperature falls below the freezing point (32°F) an average of 105 days per year. Typically the first fall freeze occurs between the beginning of October and early November, and the last spring freeze occurs between the end of March and late April.
The area receives nearly 40 inches (1,000 mm) of precipitation during an average year with the largest share being received in May and June—the April–June period averages 29 days of measurable precipitation. During a typical year the total amount of precipitation may be anywhere from 28 to 51 inches (1,300 mm). There are on average 87 days of measurable precipitation per year. Winter snowfall averages almost 16 inches, but the median is less than 9 inches (230 mm). Measurable snowfall occurs an average of 8 days per year with at least an inch of snow being received on five of those days. Snow depth of at least an inch occurs an average of 6 days per year.
Notes: Temperatures are in degrees Fahrenheit. Precipitation includes rain and melted snow or sleet in inches; median values are provided for precipitation and snowfall because meanaverages may be misleading. Mean and median values are for the 30-year period 1971–2000; temperature extremes are for the station's period of record (1900–2001). The station is located in Ottawa at 38°37′N 95°17′W, elevation 900 feet (270 m).
There were 4,697 households out of which 33.2% had children under the age of 18 living with them, 49.1% were married couplesliving together, 10.9% had a female householder with no husband present, and 35.4% were non-families. 30.5% of all households were made up of individuals, and 14.4% had someone living alone who was 65 years of age or older. The average household size was 2.43 and the average family size was 3.00.
In the city the population was spread out with 26.6% under the age of 18, 11.5% from 18 to 24, 27.7% from 25 to 44, 18.3% from 45 to 64, and 15.8% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 95.1 males. For every 100 females age 18 and over, there were 89.0 males.
The median income for a household in the city was $34,071, and the median income for a family was $41,710. Males had a median income of $30,050 versus $22,891 for females. The per capita income for the city was $16,840. About 6.8% of families and 9.0% of the population were below the poverty line, including 10.0% of those under age 18 and 8.1% of those age 65 or over.
Law and government
Ottawa was governed by a Mayor-Council system until 1913 when the City became a Commission form of government. In 1970 voters established the City Manager form of government with a five member Commission that annually selects a Mayor from its ranks. The citizens of Ottawa elect commissioners at-large. Three seats on the Commission are open every odd numbered year. Two Commissioners are elected to four-year terms and one is elected to a two-year term.