Speaking at a Fortune conference last week, Jet.com founder and Walmart.com CEO Marc Lore threw down the gauntlet when he commented that within 5 years, Walmart would achieve its goal of providing same-day grocery delivery to most of the US.  In doing so, he pointed to Walmart’s 4,700 stores, referring to the combined footprint of its Walmart and Walmart Neighborhood Market banners, which we’ve mapped below (using Chain Store Guide’s Retail Locations Database), along with its nearly 600 Sam’s Club locations.

To put Walmart’s physical footprint in context, we’ve compared it to that of the nation’s 2nd largest grocer by physical store count, The Kroger Co., below, and it’s plain to see that if anyone can beat Amazon and its Prime/Whole Foods infrastructure to the same-day delivery goal, it will be Walmart under Lore’s direction.

Turning to Amazon, it currently counts 470 Whole Foods stores and 7 distribution centers, along with approximately 350 sorting, fulfillment and distribution centers throughout the US.

It’s a bit of an apples-to-oranges comparison, and Amazon has an advantage in that it’s already offering same-day delivery on some grocery products in a number markets. But the race to nationwide same-day delivery promises to heat up.