1301 is not a country code. Numbers inside a country start like this: Accokeek, MD (United States). The first digit 1 is the trunk prefix for domestic calls and is dropped from abroad.
Have the full number? Check it in the number lookup.
| Area or operator | From abroad | Inside the country |
|---|---|---|
 Accokeek, MD · United States | +1 301 … | 1301 … |
| Beltsville, MD · United States | +1 301 … | 1301 … |
| Bethesda, MD · United States | +1 301 … | 1301 … |
| 56 more in United States | ||
| Area or operator | From abroad | Inside the country |
|---|---|---|
| Accokeek, MD · United States | +1 301 … | 1301 … |
| Beltsville, MD · United States | +1 301 … | 1301 … |
| Bethesda, MD · United States | +1 301 … | 1301 … |
| 18 more in United States | ||
If a number starts with +, the first 1–3 digits are the country code. If it starts with 0 (8 in Russia and Kazakhstan), it is a domestic number: an area or operator code follows, and from abroad the 0 or 8 is replaced with + and the country code. The same digits can mean different places, so where the call came from matters.