If you're sending a letter or package from a major city in Iowa, such as Des Moines or Cedar Rapids, to a major city in New York, such as New York City or Buffalo, it can typically take 2-3 business days for standard First-Class Mail to arrive. For Priority Mail, which offers faster delivery, it usually takes 1-2 business days.
However, if you're sending mail from a rural area in Iowa to a smaller town in New York, or if you're sending a package that requires special handling, it may take longer. Additionally, during peak mailing periods, such as the holidays, mail delivery times can be slower due to the increased volume of mail being processed.
If you need to ensure a timely delivery, you can consider using express shipping options such as Priority Mail Express or overnight delivery, which typically guarantee delivery within a specific timeframe. You can also track your mail using the USPS tracking system to get updates on its location and estimated delivery date.