Garrett County is the westernmost county of the U.S. state of Maryland. As of the 2010 census, the population was 30,097, making it the third-least populous county in Maryland. Its county seat is Oakland. The county was named for John Work Garrett (1820–1884), president of the Baltimore and Ohio Railroad. Created from Allegany County, Maryland in 1872, it was the last Maryland county to be formed.