What is the postal abbreviation for the District of Columbia?

The postal abbreviation for the District of Columbia is "DC." This abbreviation is used to represent Washington, D.C., which is the capital of the United States. It is important for mail routing and addressing, ensuring that postal services can efficiently deliver items to this specific region. The use of "DC" helps to distinguish it from other states and territories, as the District of Columbia is not a state but a federal district established by the U.S. Constitution.

The other options do not represent the District of Columbia; "CO" is the abbreviation for Colorado, "CA" represents California, and "DM" is not a recognized postal abbreviation for any U.S. state or territory. Understanding these abbreviations is crucial for anyone involved in postal services or requiring familiarity with U.S. geography.