Title 4 of the United States Code outlines the role of flag of the United States, Great Seal of the United States, Washington, DC, and the states in the United States Code. [1]
Chapter 1: The Flag
Note that 36 U.S.C. § 110 is where Flag Day is codified.
Chapter 2: The Seal
Chapter 3: Seat of the Government
Chapter 4: The States
Chapter 5: Official Territorial Papers