Mayville is a city in Traill County, North Dakota, United States. The population was 1,854 at the 2020 census. which makes Mayville the largest community in Traill County. Mayville was founded in 1881. The city's name remembers May Arnold, the first white child born in the immediate area. 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.