[12] Early German settlers established themselves in and around Franklin County, including what would later be known as Union.

German architecture, culture, and especially surnames are still prevalent around Union and surrounding areas.

[13] According to the United States Census Bureau, the city has a total area of 9.16 square miles (23.72 km2), all land.

[14] The 2020 United States census[16] counted 12,348 people, 4,686 households, and 3,023 families in Union.

The elected, policy-making body of the City consists of a Mayor and an eight-member Board of Aldermen.

Missouri Eastern Railroad, a division of Jaguar Transport, provides regular freight rail service to industrial customers located in Union.

MER operates the far eastern segment of the former Chicago, Rock Island and Pacific Railway's St. Louis to Kansas City main line that was constructed in 1870.

[19] The active portion of the former CRI&P line runs from the north side of St. Louis, where it connects with the Terminal Railroad Association of St. Louis and Union Pacific Railroad, and now terminates in Union, Missouri.

A proposal for an expressway to bypass the junction of US 50 and Route 47 was cancelled due to complications.

[21] There is another proposal to make US 50 from Union to I-44 four lanes and eventually through the rest of Franklin County.

[25][26] Union also has one private Catholic school, Immaculate Conception (Serving Pre-K to eighth grade).

Union is home to East Central College, which offers two-year degrees and certificates.

[27] The Missouri Meerschaum company, founded in 1869 is the first and oldest manufacturer of corn-cob pipes.

In 1907, The National Cob Pipe Works was opened to help fulfill the need for jobs in the area.

[28] Presently, there are over 300 businesses in Union, including the presence of manufacturers such as the Esselte Pendaflex Corporation and Silgan Plastic Containers.