The Monroe Avenue Commercial Buildings, also known as the Monroe Block, is a historic district located along a block-and-a-half stretch at 16-118 Monroe Avenue in Detroit, Michigan, just off Woodward Avenue at the northern end of Campus Martius. The district was designated a Michigan State Historic Site in 1974 and listed on the National Register of Historic Places in 1975. The thirteen original buildings were built between 1852 and 1911 and ranged from two to five stories in height. The National Theatre, built in 1911, is the oldest surviving theatre in Detroit, a part of the city's original theatre district of the late 19th century, and the sole surviving structure from the original Monroe Avenue Commercial Buildings historic period.