Sources:  U.S. 2020 Census and the American Community Survey of 2019:   

According to the U.S. 2020 census, there are 1,763 people, 703 households, and 483 families residing in the Borough of Mayfield. The population density is 730.4 people per square mile. Mayfield comprises 2.4 square miles. The racial makeup of the borough is 96.6% White, .8% Black or African American, 0% Native American, .6% Asian, .3% from other races, and 1.7% from two or more races. Hispanic or Latino of any race are .9% of the population.

In the 703 households, 30% have children under the age of 18 living with them, 51% are married couples living together, 13% have a female householder with no spouse present, 4% have a male householder with no spouse and 31% are non-families. 25.6% of households are made up of individuals, and 11.1% are one person aged 65 or older. The average household size is 2.42 and the average family size is 2.9.

23.7% are 19 and under,13.6% are between 20 and 34,17.2% are between 35 and 49, 27.4% are between 50 and 64, 13.3% are between 65 and 79, and 5.3% are 80 and older. The median age is 46.6 years. 46.6% are males and 53.4% are females.  For every 100 females, there are 87.3 males. 

The median household income is $67,969 (average household income $73,720) . About 9.5% are below the poverty level.   

The median property value is $134,000 and home ownership rate is 88.2%.