The head of the US Postal Service has warned lawmakers that the storied 250-year-old agency is at a "critical juncture" and will run out of cash in less than a year unless Congress allows it to borrow more money and charge more for postage.

Why it matters: Even as major retailers build their own logistics networks, millions of Americans -- especially in rural areas -- still rely on USPS for essentials like prescription medications and last-mile delivery.