密夫林县（Mifflin County, Pennsylvania）是美国宾夕法尼亚州中南部的一个县。面积1,074平方公里。根据美国2000年人口普查，共有人口46,486。县治路厄斯堡。

成立于1789年9月19日，县名纪念首任州长汤玛斯·密夫林。

Mifflin County is a county located in the U.S. state of Pennsylvania. As of the 2010 census, the population was 46,682. Its county seat is Lewistown. The county was created on September 19, 1789, from parts of Cumberland County and Northumberland County and named after Thomas Mifflin, the first Governor of Pennsylvania.