Mayville is often grouped with the neighboring city of Portland. The two towns are sometimes given the name May-Port. Mayville State University is located in Mayville.
As of the census of 2000, there were 1,953 people, 752 households, and 417 families residing in the city. The population density was 1,216.7 people per square mile (468.4/km²). There were 876 housing units at an average density of 545.7/sq mi (210.1/km²). The racial makeup of the city was 97.49% White, 0.26% African American, 1.48% Native American, 0.26% Asian, 0.05% Pacific Islander, 0.31% from other races, and 0.15% from two or more races. Hispanic or Latino of any race were 0.46% of the population.
There were 752 households out of which 23.8% had children under the age of 18 living with them, 46.1% were married couples living together, 6.6% had a female householder with no husband present, and 44.5% were non-families. 35.0% of all households were made up of individuals and 18.1% had someone living alone who was 65 years of age or older. The average household size was 2.16 and the average family size was 2.82.
In the city the population was spread out with 17.8% under the age of 18, 23.5% from 18 to 24, 18.3% from 25 to 44, 17.2% from 45 to 64, and 23.3% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 93.2 males. For every 100 females age 18 and over, there were 89.5 males.
The median income for a household in the city was $34,635, and the median income for a family was $44,931. Males had a median income of $34,107 versus $21,615 for females. The per capita income for the city was $17,079. About 6.2% of families and 13.4% of the population were below the poverty line, including 12.4% of those under age 18 and 6.2% of those age 65 or over.