McMillan is an unincorporated community in San Saba County, in the U.S. state of Texas.

McMillan was named for Texas Ranger Captain Newton D. McMillin in the late 1850s.

House petitioned for a post office to be established here on October 6, 1904, but it opened in Bomar.

Meeks sold his store to local settler Hugh Miller that same year.

Still another was built circa 1923 and joined the San Saba Independent School District in 1933.