Amazon is expanding its same-day grocery delivery service to 1,000 cities and towns across the U.S., the company said Wednesday.

Amazon has positioned itself as America's most prominent shopping retailer, and a large part of that dominance is the two-day shipping offered for most items on the site. Customers with Amazon Prime are able to have items to their door within 48 hours of ordering,

Amazon Prime members in over 1.000 cities and towns can now get same-day grocery deliveries for free. Find out if it's available for you and how it works.