For a USPS letter to reach a state 3 states away, it usually takes around 3 days.
However it can also take as long as 5 to 6 days in some cases for the USPS letter to reach a state 3 states away.
Also if you mail the letter through USPS on Friday evening or on Saturday or Sunday it can take longer to reach the destination.
I've had some letters get to me within 3 days that were 3 states away and sometimes it's taken 5 to 6 days and even 7 days in some cases to get a letter 3 states away.
And if there's any bad weather or disruptions, it can delay the mail.
The USPS mail is also now taking a bit longer than it used to.