It’s pretty speedy, but it does depend on where you're located in the US.
Generally, orders going to the east coast will arrive quicker than those on the west coast (there’s a lot of ground to cover across the pond!), and from the point of dispatch, orders tend to be delivered within 7 working days.
DHL deliver parcels from Monday to Friday between 8am and 6pm. If you are not at home when the courier tries to deliver your parcel, you will find a missed delivery note in your mailbox. You can also manage your shipment on DHL's On Demand Delivery site, which has an array of in-flight options.