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Nineteen states have only one telepohone area code for the entire state.

Does the second word state mean the whole country? Please advise.

LC
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No, in this case, it is referring to one of the United States.

I know that the states of Maine and Delaware are two of the 19 that have only one area code each. The smaller the population, the fewer telephone numbers, and the more likely they can keep to one area code for the entire state. It's nice, becuase you can dial just the seven digits in the phone number, instead of 1-area code-seven digits. Seems silly to dial 10 digits just to reach your next door neighbor.
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Ok. I understand now. Unlike California which contains many area codes such as 415, 408, 510, 626, etc, these 19 states only have one area code each. In the first place, I thought they shared only one code. So I misunderstood the meaning of the sentence. Thanks.

LC
Yes, the addition of the word "each" probably would have made it clear from the beginning.