Nanty Glo is located in west-central Cambria County at in the valley of the South Branch of Blacklick Creek, a west-flowing tributary of the Conemaugh River and part of the Ohio River basin. Ebensburg, the Cambria County seat, is 7 miles (11 km) to the east, and Johnstown is 12 miles (19 km) to the southwest.(40.472096, −78.834777),
According to the United States Census Bureau, the borough of Nanty Glo has a total area of 1.9 square miles (4.8 km2), of which 29,190 square feet (2,712 m2), or 0.06%, is water.
The 2010 census found the population of the town to be 2,734 people. The borough population growth from 2000 to 2010 was -10.5% (down from 3,054 people to 2,734 people). 21.3% of Nanty Glo borough residents were under 18 years of age. Census 2010 race data for Nanty Glo show a racial breakdown of 0.4% black, 0.1% Asian, and 0.9% Hispanic. There were 1,289 housing units in Nanty Glo borough, 91.0% of which were occupied.
As of the census of 2000, there were 3,054 people, 1,272 households, and 856 families residing in the borough. The population density was 1,670.1 people per square mile (644.3/km²). There were 1,362 housing units at an average density of 744.8 per square mile (287.4/km²). The racial makeup of the borough was 99.41% White, 0.23% African American, 0.03% Native American, 0.03% from other races, and 0.29% from two or more races. Hispanic or Latino of any race were 0.29% of the population. 15.3% were of German, 12.0% Italian, 11.1% Polish, 9.9% Irish, 9.0% Slovak, 9.0% American and 7.0% English ancestry according to Census 2000.
There were 1,272 households, out of which 25.9% had children under the age of 18 living with them, 50.0% were married couples living together, 13.0% had a female householder with no husband present, and 32.7% were non-families. 29.9% of all households were made up of individuals and 18.4% had someone living alone who was 65 years of age or older. The average household size was 2.39 and the average family size was 2.95.