Mill Hall is a borough in Clinton County, Pennsylvania, United States. The population was 1,613 at the 2010 census.

Clinton County is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population was 37,450. Its county seat is Lock Haven. The county was created on June 21, 1839, from parts of Centre and Lycoming Counties. Its name is in honor of the sixth Governor of New York, DeWitt Clinton. Some alternate sources suggest the namesake is Henry Clinton. Clinton County comprises the Lock Haven, PA Micropolitan Statistical Area, which is also included in the Williamsport-Lock Haven, PA Combined Statistical Area. The county is part of the Central Pennsylvania region of the state.