Jefferson City, also known informally as Jeff City, is the capital of the U.S. state of Missouri. It serves as the county seat of Cole County and functions as the principal city of the Jefferson City Metropolitan Statistical Area. While it ranks as the 16th most populous city in Missouri, it is the ninth least populous state capital in the United States.
The city's population was recorded at 43,228 during the 2020 United States census. Geographically, the majority of Jefferson City is situated within Cole County, though a small northern portion extends into Callaway County. It also forms part of the nine-county Columbia–Jefferson City–Moberly combined statistical area.