The Old Masonic Hall, also known as Benicia Masonic Hall, is a historic building in Benicia, California.. Constructed by Benicia Lodge No. 5, in 1850, it was the first purpose build Masonic Hall in California. The first floor was used as the Solano County court room and offices, the second floor held rooms for the Lodge. The Masons occupied the building until 1887, when the Lodge outgrew the premises. The building was sold, became a public meeting hall until 1950, when the lodge repurchased the building. The building was listed on the National Register of Historic Places in 1972.