Have you ever wondered where those blueish-gray Amazon delivery trucks with independent drivers load up? Most do at what Amazon calls “last mile” delivery stations, and the company continues to add more in the D.C. region.

Amazon opened a new one in Beltsville, Maryland, in late October, and has opened two more this week in Landover and Laurel.

The Beltsville location, at 10406 Tucker Street, is a 264,000-square-foot facility. The Landover location, at 5801 Columbia Park Road, is 172,000-square-feet, and the Laurel facility, at 14601 Sweitzer Lane, is 150,000-square-feet.

Amazon also recently opened delivery stations in Lanham and Upper Marlboro.

Packages make their way to these last-mile delivery stations from nearby Amazon fulfillment and sortation centers, where they are loaded on to trucks, many of them through Amazon’s Delivery Service Partner Program. Independent contractors can find information about delivering for Amazon through its Flex program.

Most independent Flex drivers earn between $18 and $25 an hour.

These facilities also have hundreds of full and part-time Amazon jobs each.

Amazon has four large distribution facilities in Maryland, as well as 20 fulfillment and sorting centers and delivery stations in Virginia.

Earlier this month, Amazon announced plans for a 630,000-square-foot East Coast hub for repacking and distributing third-party vendors’ merchandise to other distribution centers.