**Wellersburg** is a borough in Somerset County, Pennsylvania, United States. It is part of the Johnstown, Pennsylvania Metropolitan Statistical Area. The population was 176 at the 2000 census.

Wellersburg is located at 39°43′51″N 78°51′05″W.

According to the United States Census Bureau, the borough has a total area of 0.8 square miles (2.1 km^{2}), all of it land.

As of the census of 2000, there were 176 people, 84 households, and 51 families residing in the borough. The population density was 223.4 people per square mile (86.0/km^{2}). There were 90 housing units at an average density of 114.2 per square mile (44.0/km^{2}). The racial makeup of the borough was 98.86% White, and 1.14% from two or more races.

There were 84 households out of which 15.5% had children under the age of 18 living with them, 45.2% were married couples living together, 10.7% had a female householder with no husband present, and 38.1% were non-families. 36.9% of all households were made up of individuals and 17.9% had someone living alone who was 65 years of age or older. The average household size was 2.10 and the average family size was 2.63.

In the borough the population was spread out with 15.9% under the age of 18, 6.8% from 18 to 24, 28.4% from 25 to 44, 27.3% from 45 to 64, and 21.6% who were 65 years of age or older. The median age was 44 years. For every 100 females there were 83.3 males. For every 100 females age 18 and over, there were 87.3 males.

The median income for a household in the borough was $21,111, and the median income for a family was $23,750. Males had a median income of $24,688 versus $18,750 for females. The per capita income for the borough was $14,495. About 4.3% of families and 5.4% of the population were below the poverty line, including none of those under the age of eighteen or sixty five or over.