Reservoir is an unincorporated community and census-designated place (CDP) in Blair County, Pennsylvania, United States.

It is on the south side of the valley of the Frankstown Branch Juniata River.

Hollidaysburg, the Blair county seat, is 4 miles (6 km) to the north by road.

Loop Mountain rises to the southeast to an elevation of 2,495 feet (760 m).

This Blair County, Pennsylvania state location article is a stub.