Byrnes Mill is a city in northern Jefferson County, Missouri, United States.

[6] The city is located on the Big River, and has the ruins of an old mill and dam.

19.6% of all households were made up of individuals, and 4.9% had someone living alone who was 65 years of age or older.

15.1% of all households were made up of individuals, and 3.4% had someone living alone who was 65 years of age or older.

In Fiscal Year 2013, the Byrnes Mill Municipal Court collected $443,000 in fines on 3,888 cases.

For its 2012-2013 budget, Byrnes Mill projected the fines from its Municipal Court would account for 30.6% of total city revenue.

[8][9][10][11] As of April 11, 2015, Byrnes Mill is actively opposing Missouri Senate Bill 5 (2015)[12] which would limit the amount of income it could obtain from its Municipal Court to 20% the first year and 10% the following year.

The Byrnes Mill Website states on its front page: "It could mean we will no longer be able to support our Police Department and court system.